Hard coat film

ABSTRACT

A hard coat film excellent in abrasion resistance and saponification resistance. A hard coat layer includes a cured product of a curable resin composition containing a reactive inorganic fine particle having an average particle diameter of 5 nm to 30 nm, and has a skin layer, wherein the reactive inorganic fine particles are localized, in its surface region being an interface and its vicinity on a side opposite to a transparent substrate film side of the hard coat layer. Alternatively, the reactive inorganic fine particle has an average particle diameter of 30 nm to 100 nm, and has density distribution in a thickness direction of the hard coat layer lowest at an interface on a side opposite to a transparent substrate film side of the hard coat layer while the density is highest at an interface and its vicinity on the transparent substrate film side of the hard coat layer.

TECHNICAL FIELD

The present invention relates to a hard coat film in which a hard coatlayer is provided on a transparent substrate film, and which is used forprotecting the surface of a display such as a liquid crystal display,CRT display, projection display, plasma display or electroluminescencedisplay.

BACKGROUND ART

It has been required that the image display surface of an image displaydevice such as a liquid crystal display (LCD) and a cathode ray tube(CRT) display be imparted with abrasion resistance to avoid beingscratched upon handling. To meet the request, in general, an opticallaminate (hereinafter, it may be referred to as a hard coat film), whichcomprises a hard coat (HC) layer provided on a substrate film, is usedto increase the abrasion resistance of the image display surface of animage display device.

Examples of techniques of hardening a plastic surface generally includemethods of forming a metallic thin film by coating anorganosiloxane-based or melamine-based heat-curable resin, by the vacuumdeposition method or sputtering method using such a resin, and bycoating a polyfunctional acrylate-based active energy ray-curable resin.

As another method of improving the hardness of a hard coat layer, theremay be a method of adding inorganic fine particles, generally in which ahard coat film provided with a hard coat layer having inorganic fineparticles added on a substrate film is produced.

Meanwhile, an optical film used as an antireflection film attached ordisposed on the surface of a display for the purpose of antireflectionof outside light to improve images is known (for example, see PatentLiterature 1).

The optical film comprises a cured layer formed on a transparent plasticsubstrate film. Patent Literature 1 discloses that an apparently lowrefractive index layer can be formed, and excellent antireflectiveproperties can be obtained by unevenly distributing hollow silica beinglow-refractive-index fine particles on the surface side of the curedlayer (the side opposite to the substrate film side). Patent Literature1 discloses that hollow silica having an average particle diameter of 30nm or more to further decrease refractive index by increasing the ratioof voids, and hollow silica having an average particle diameter of 40 nmis used in Examples. In order to unevenly distribute hollow silica onthe surface side of the cured layer, hollow silica is subjected tosurface treatment with a fluorine-containing compound to decreasesurface free energy.

CITATION LIST

-   [Patent Literature 1] Japanese Patent Application Laid-Open (JP-A)    No. 2007-086764

SUMMARY OF INVENTION Technical Problem

High abrasion resistance is required for hard coat films. A first objectof the present invention is to provide a hard coat film having superiorabrasion resistance to conventional hard coat films.

Also, there is another problem from another point of view. In productionof the above image display, it is difficult to attach the substrate filmside of the hard coat film directly on a polarizer using an adhesive(including tackiness agent). Thus, the surface of the substrate film isrequired to be subjected to chemical surface treatment (saponificationtreatment) by alkali.

However, there is a problem that when the hard coat film is used anddipped in an alkali solution, inorganic fine particles in the interfaceand its vicinity on the side opposite to the substrate film side of thehard coat layer elute or drop into the alkali solution. Also, there is aproblem that when the amount of the inorganic fine particles containedin the hard coat layer is increased, the hardness of the hard coat filmimproves, but simultaneously the amount of the inorganic fine particlesin the interface and its vicinity on the side opposite to the substratefilm side of the hard coat layer increases, and the amount of theinorganic fine particles which elute or drop into the alkali solutionalso increases upon saponification treatment.

Therefore, conventionally, after a protecting film is provided on thesurface of the hard coat layer provided on the substrate film,saponification treatment is performed for the purpose of protecting thehard coat layer from an alkali solution.

However, a hard coat film capable of resisting saponification treatmentwithout the protecting film is required for further reduction of theproduction cost.

A second object of the present invention is to provide a hard coat filmhaving high abrasion resistance and saponification resistance.

Solution to Problem

According to the present invention, a first aspect of the presentinvention herein after described is provided to attain the above firstobject, and a second aspect of the present invention hereinafterdescribed is provided to attain the above second object.

As a result of diligent researches made to attain the above objects, theinventors of the present invention found out that when reactiveinorganic fine particles having a specific particle size are containedin a hard coat layer, the reactive inorganic fine particles can belocalized in the surface region of the hard coat layer, and have reacheda hard coat film excellent in abrasion resistance.

A hard coat film according to a first aspect of the invention is a hardcoat film in which a hard coat layer is provided on a transparentsubstrate film,

wherein the hard coat layer comprises a cured product of a curable resincomposition containing:

a reactive inorganic fine particle (A) having an average particlediameter of 5 nm to 30 nm, and having a reactive functional group (a)introduced by an organic component, which covers at least a part of asurface of the reactive inorganic fine particle (A), on the surface, and

a curable binder system containing a binder component (B) having areactive functional group (b) cross-linkingly reactive with the reactivefunctional group (a) of the reactive inorganic fine particle (A), andthe curable binder system itself also having curing reactivity;

wherein the hard coat layer has a skin layer in its surface region beingan interface and its vicinity on a side opposite to a transparentsubstrate film side of the hard coat layer, in which the skin layer hashigher average particle number of the reactive inorganic fine particle(A) per unit area of a thickness-directional cross section of the hardcoat layer than a region of the hard coat layer closer to thetransparent substrate film side than the surface region; and

wherein an average particle number of the reactive inorganic fineparticle (A) per unit area of a thickness-directional cross section ofthe skin layer is twice or more than that of the reactive inorganic fineparticle (A) per unit area of the thickness-directional cross section ofthe hard coat layer.

According to the first aspect of the invention, the reactive inorganicfine particles (A) aggregate at the interface on the side opposite tothe transparent substrate film side of the hard coat layer to form theskin layer, and since the skin layer has high hardness and film strengthdue to increase in crosslinking point by the reactive functional group(a) of the reactive inorganic fine particle (A) and the reactivefunctional group (b) of the binder component (B) and the hardness of thereactive inorganic fine particles (A), a hard coat film excellent inhard coating performance can be obtained.

In the hard coat film of the first aspect of the invention, a thicknessof the skin layer is preferably a thickness from the interface on theside opposite to the transparent substrate film side to the averageparticle diameter of the reactive inorganic fine particle (A) up totwice of the average particle diameter to further increase the effect ofimproving the hard coating performance by the skin layer. Also, thereactive inorganic fine particles (A) are preferably aggregated in theskin layer.

Further, the average particle number of the reactive inorganic fineparticle (A) per unit area of the thickness-directional cross section ofthe skin layer is preferably 2,000/μm² or more, and an average particlenumber of the reactive inorganic fine particle (A) per unit area of thethickness-directional cross section of the whole hard coat layer ispreferably 2,000/μm² or less.

Also, as the reactive inorganic fine particle (A), a reactive inorganicfine particle (A) containing no fluorine can be used.

According to the first aspect of the invention, a hard coat filmprovided with a hard coat layer, wherein the surface of the hard coatlayer has no scratch after a steel wool scratch test, in which thesurface of the hard coat layer is frictioned with #0000 steel wool byreciprocating the steel wool with a load of 500 g/cm² for 10 times at aspeed of 50 mm/sec, and excellent in hard coating performance can beprovided.

In the hard coat film of the first aspect of the invention, a layerthickness of the hard coat layer is preferably from 2 to 30 μm from theviewpoint of excellent production of the hard coat layer.

As a result of diligent researches made to attain the above objects, theinventors of the present invention found out that by adding the reactiveinorganic fine particles (A) having a specific particle size differentfrom that of the first aspect of the invention in the curable bindersystem used for the hard coat layer, a hard coat film having highabrasion resistance and excellent in saponification resistance can beobtained. Based on the above knowledge, the inventor has reached asecond aspect of the invention.

A hard coat film according to the second aspect of the invention is ahard coat film in which a hard coat layer is provided on a transparentsubstrate film,

wherein the hard coat layer comprises a cured product of a curable resincomposition for the hard coat layer containing:

a reactive inorganic fine particle (A) having an average particlediameter of 30 nm to 100 nm, and having a reactive functional group (a)introduced by an organic component, which covers at least a part of asurface of the reactive inorganic fine particle (A), on the surface, and

a curable binder system containing a binder component (B) having areactive functional group (b) cross-linkingly reactive with the reactivefunctional group (a) of the reactive inorganic fine particle (A), andthe curable binder system itself also having curing reactivity; and

wherein the reactive inorganic fine particle (A) has densitydistribution in a thickness direction of the hard coat layer, in whichdensity of the reactive inorganic fine particle (A) is lowest at aninterface on a side opposite to a transparent substrate film side of thehard coat layer while the density of the reactive inorganic fineparticle (A) is highest at an interface and its vicinity on thetransparent substrate film side of the hard coat layer.

Since the reactive inorganic fine particle (A) has high hardness, thereactive inorganic fine particle (A) is hardly crushed by pressure(external pressure) applied to the particle from outside and hasexcellent pressure resistance. Also, since the reactive inorganic fineparticle (A) has the reactive functional group (a) cross-linkinglyreactive with the reactive functional group (b) of the binder component(B), the reactive inorganic fine particle (A) can crosslink with thebinder component (B). Hence, since the hard coat layer of the presentinvention contains the reactive inorganic fine particles (A) having highhardness, the hard coat layer of the present invention has highhardness. Further, since the reactive inorganic fine particles (A) andthe binder component (B) form plural crosslinking points, the filmstrength of the hard coat layer improves and the hard coat layer of thepresent invention exhibits excellent abrasion resistance.

By setting the particle size of the reactive inorganic fine particle (A)within the above range, the diffusion coefficient of the reactiveinorganic fine particle (A) becomes small, and thereby, the number ofthe reactive inorganic fine particle (A) present (density distribution)varies in the thickness direction of the hard coat layer. Specifically,the density of the reactive inorganic fine particle (A) is lowest at theinterface and its vicinity on the side opposite to the transparentsubstrate film side of the hard coat layer while the density of thereactive inorganic fine particle (A) is highest at the interface and itsvicinity on the transparent substrate film side of the hard coat layer.Hence, the hard coat film using the hard coat layer can decrease thenumber of the reactive inorganic fine particles (A) which elute or dropfrom the surface of the hard coat layer into an alkali solution uponsaponification treatment, and can improve the saponification resistance.Thereby, a protecting film for saponification treatment of the hard coatfilm is not necessary, so that the number of processes and material costcan be reduced.

In the hard coat film of the second aspect of the invention, when athickness-directional cross section of the hard coat layer is defined asP1 and a vertical-directional density of the reactive inorganic fineparticle (A) in the cross section P1 is defined as a number(particles/μm²) of the reactive inorganic fine particle (A) per unitarea of the cross section P1, density of the reactive inorganic fineparticle (A) at any part in an region from the interface on the sideopposite to the transparent substrate film side to 500 nm in depth ofthe cross section P1 is preferably 150 particles/μm² or less.

Further, a number of the reactive inorganic fine particle (A) partiallyprojected from the interface on the side opposite to the transparentsubstrate film side of the hard coat layer is preferably 150 or less perunit area of the interface.

By setting the density of the reactive inorganic fine particle (A) orthe number of the reactive inorganic fine particle (A) present in theabove ranges, the number of the reactive inorganic fine particles (A)which elute or drop from the surface of the hard coat layer uponsaponification treatment can be decreased. Thereby, the saponificationresistance of the hard coat film of the present invention can beimproved.

In the hard coat film of the second aspect of the invention, when aplanar-directional cross section of the hard coat layer is defined as P2and a planar-directional density of the reactive inorganic fine particle(A) in the cross section P2 is defined as a number (particles/μm²) ofthe reactive inorganic fine particle (A) per unit area of the crosssection P2, difference of densities of the reactive inorganic fineparticle (A) of two parts in the cross section P2 at any height of thehard coat layer is preferably 30 particles/μm² or less from theviewpoint of improvement of the hardness of a cured film.

In the hard coat film of the second aspect of the invention, hardness ofthe hard coat layer when a pencil hardness test in accordance with JISK5600-5-4 (1999) is performed with a load of 500 g is preferably 4H ormore from the viewpoint of abrasion resistance and prevention ofscratch.

In the hard coat film of the second aspect of the invention, layerthickness of the hard coat layer is preferably from 1 μm to 100 μm.

In the hard coat film of the first and second aspects of the invention,at least a part of the surface of the reactive inorganic fine particle(A) is covered by the organic component, the reactive functional group(a) is introduced on the surface of the reactive inorganic fine particle(A) by the organic component, and the organic component is contained by1.00×10⁻³ g/m² or more per unit area of the inorganic fine particlebefore being covered from the viewpoint of improving the hardness of acured film.

In the hard coat film of the first and second aspects of the invention,the reactive functional group (a) of the reactive inorganic fineparticle (A) and the reactive functional group (b) of the bindercomponent (B) preferably have a polymerizable unsaturated group from theviewpoint of hard coating performance.

Also, from the viewpoint of improving the film strength even if theamount of the organic component content is small, the reactive inorganicfine particles (A) are preferably obtained by dispersing inorganic fineparticles in water and/or an organic solvent serving as a dispersionmedia in the presence of one or more kinds of surface modificationcompounds having a molecular weight of 500 or less selected from thegroup consisting of saturated or unsaturated carboxylic acid, acidanhydride, acid chloride, ester and acid amide corresponding to thecarboxylic acid, amino acid, imine, nitrile, isonitrile, an epoxycompound, amine, a β-dicarbonyl compound, silane and a metallic compoundhaving a functional group.

From the viewpoint of being capable of efficient surface modification ofthe reactive inorganic fine particle (A) with the organic component, thesurface modification compound is a compound having a hydrogenbond-forming group. Also, from the viewpoint of easy formation of acrosslinking bond between the reactive functional group (a) introducedto the reactive inorganic fine particle (A) and the reactive functionalgroup (b) of the binder component (B) and further improvement of thefilm strength, at least one kind of the surface modification compoundpreferably has a polymerizable unsaturated group to be the reactivefunctional group (a).

From the viewpoint of improving dispersibility to the organic componentand the film strength, the reactive inorganic fine particles (A) arepreferably obtained by bounding a compound containing the reactivefunctional group (a) being introduced on the surface of the reactiveinorganic fine particle (A), a group represented by the followingchemical formula (1), and a silanol group or a group producing thesilanol group by hydrolysis, with metal oxide fine particles:

-Q¹-C(=Q²)-NH—  Chemical formula (1)

wherein Q¹ is NH, O (oxygen atom) or S (sulfur atom); and Q² is O or S.

The binder component (B) is preferably a compound having three or morereactive functional groups (b). The binder component (B) is morepreferably a compound having three or more reactive functional groups(b) capable of bonding with the reactive functional group (a) of thereactive inorganic fine particle (A).

A content of the reactive inorganic fine particle (A) is preferably from10 to 60 wt % with respect to a total solid content.

In the hard coat film of the present invention, it is preferable thatthe transparent substrate film mainly comprises cellulose acylate, acycloolefin polymer, an acrylate-based polymer or polyester.

Advantageous Effects of Invention

The hard coat film according to the first aspect of the invention hasexcellent hard coating performance since the hard coating performance ofthe hard coat layer is improved by unevenly distributing the reactiveinorganic fine particles having a specific particle diameter and havingthe reactive functional group capable of forming a crosslinking bondwith the binder component forming the hard coat layer at the surfaceregion being the interface and its vicinity on the side opposite to thetransparent substrate film side of the hard coat layer.

In the hard coat film according to the second aspect of the invention,the density of the reactive inorganic fine particle (A) is lowest at theinterface on the side opposite to the transparent substrate film side ofthe hard coat layer while the density of the reactive inorganic fineparticle (A) is highest at the interface and its vicinity on thetransparent substrate film side of the hard coat layer. Hence, the hardcoat film using the hard coat layer can decrease the number of thereactive inorganic fine particles (A) which elute or drop from thesurface of the hard coat layer into an alkali solution uponsaponification treatment, and can improve the saponification resistance.Thereby, a protecting film for saponification treatment of the hard coatfilm is not necessary, so that the number of processes and material costcan be reduced.

Also, since the reactive functional group (a) of the reactive inorganicfine particle (A) and the reactive functional group (b) of the curablebinder component (B) contained in the curable binder system form acrosslinking bond, the hard coat film can have high hard coatingperformance.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view schematically showing an example of a hardcoat film of the first aspect of the invention.

FIG. 2 is a schematic view to explain a skin layer of the first aspectof the invention.

FIG. 3 is a view showing a basic layer constitution of a hard coat filmof the second aspect of the invention.

FIG. 4 is a view schematically showing an example of the distribution ofthe reactive inorganic fine particles (A) of the thickness-directionalcross section of the hard coat film of the second aspect of theinvention.

FIG. 5 is a view schematically showing an example of the distribution ofthe reactive inorganic fine particles (A) in the planar-directionalcross section of the hard coat film of the second aspect of theinvention.

REFERENCE SIGNS LIST

-   -   1: Hard coat layer    -   2: Transparent substrate film    -   4: Reactive inorganic fine particle (A)    -   5: Skin layer    -   10: Hard coat film    -   30: Interface on the side opposite to the transparent substrate        film side of a hard coat layer 40: Interface on the transparent        substrate film side of a hard coat layer    -   P1: Thickness-directional cross section of the hard coat layer    -   P2: Planar-directional cross section of the hard coat layer

DESCRIPTION OF EMBODIMENTS

Hereinafter, a hard coat film of a first aspect and a second aspect ofthe invention of will be further explained. Firstly, the first aspect ofthe invention will be explained, and then, the second aspect of theinvention will be explained. Upon explaining the second aspect of theinvention, the explanation in common with the first aspect of theinvention is abbreviated.

1. Explanation of First Aspect

A hard coat film of a first aspect of the invention is a hard coat filmin which a hard coat layer is provided on a transparent substrate film,

wherein the hard coat layer comprises a cured product of a curable resincomposition containing:

a reactive inorganic fine particle (A) having an average particlediameter of 5 nm to 30 nm, and having a reactive functional group (a)introduced by an organic component, which covers at least a part of asurface of the reactive inorganic fine particle (A), on the surface, and

a curable binder system containing a binder component (B) having areactive functional group (b) cross-linkingly reactive with the reactivefunctional group (a) of the reactive inorganic fine particle (A), andthe curable binder system itself also having curing reactivity;

wherein the hard coat layer has a skin layer in its surface region beingan interface and its vicinity on a side opposite to a transparentsubstrate film side of the hard coat layer, in which the skin layer hashigher average particle number of the reactive inorganic fine particle(A) per unit area of a thickness-directional cross section of the hardcoat layer than a region of the hard coat layer closer to thetransparent substrate film side than the surface region; and

wherein an average particle number of the reactive inorganic fineparticle (A) per unit area of a thickness-directional cross section ofthe skin layer is twice or more than that of the reactive inorganic fineparticle (A) per unit area of the thickness-directional cross section ofthe hard coat layer.

Herein, the skin layer is a layer structure wherein the reactiveinorganic fine particles (A) are unevenly distributed in the surfaceregion which is from an interface (i.e. air interface) on the sideopposite to the transparent substrate film side of the hard coat layerto a certain depth, and constitutes the outer most surface of the airinterface side of the hard coat layer. The skin layer contains morereactive inorganic fine particles (A) than the region in the hard coatlayer closer to the transparent substrate film side than the surfaceregion. In the hard coat layer, the average particle number of thereactive inorganic fine particles (A) per unit area of thethickness-directional cross section of the hard coat layer sharplydecreases from a certain depth away from the interface on the sideopposite to the transparent substrate film side towards the transparentsubstrate film side, thus, a border of the skin layer can be clearlydetermined. The average particle number of the reactive inorganic fineparticles (A) per unit area of the thickness-directional cross sectionof the skin layer is twice or more than the average particle number ofthe reactive inorganic fine particles (A) per unit area of thethickness-directional cross section of the whole hard coat layerincluding the skin layer.

FIG. 1 shows an example of one embodiment of the hard coat film of thefirst aspect of the invention. In the hard coat film 10 shown in FIG. 1,the hard coat layer 1 is directly provided on one surface of thetransparent substrate film 2. The hard coat layer 1 has the skin layer5, in which reactive inorganic fine particles 4 are unevenly distributedat the interface on the side opposite to the transparent substrate film2 side of the hard coat layer 1.

The distribution state of reactive inorganic fine particles (A) in thehard coat layer 1 of the hard coat film of the first aspect of theinvention will be explained with reference to FIG. 2.

In the thickness-directional cross section of the hard coat layer 1, aregion which is surrounded by an interface la on the transparentsubstrate film 2 side, an interface (air side interface) 1 b on the sideopposite to the transparent substrate film side and two sides parallelto the thickness direction of the hard coat layer 1 is referred to as aregion S. The average particle number P of the reactive inorganic fineparticles (A) per unit area of the region S is defined as the averageparticle number of the reactive inorganic fine particles (A) per unitarea of the thickness-directional cross section of the whole hard coatlayer.

In the region S, when the average particle number p₁ per unit area ofthe region S₁ from the air side interface to a certain depth D₁ ismeasured, p₁>P×2. When the average particle number p per unit area ofthe region S from the air side interface to the depth D being deeperthan D₁ is measured, the average particle number p_(m) per unit area isp_(m)=P×2 at the depth D_(m). In the region S_(m+1) having a depth fromthe air side interface of D_(m+1) being deeper than D_(m), the averageparticle number p_(m+1) per unit area is p_(m+1)<P×2. Herein, the regionS_(m) from the air interface side to the depth D_(m) can be consideredas the skin layer 5.

The distribution state of the reactive inorganic fine particles (A) inthe hard coat layer can be confirmed by the scanning transmissionelectron microscope (STEM) photograph etc. of the hard coat layer. Theborder of the skin layer having reactive inorganic fine particles (A)unevenly distributed can be visually determined.

Also, the average particle number of the reactive inorganic fineparticles (A) per unit area of the thickness-directional cross sectionof the hard coat layer can be obtained as below. That is, the averageparticle number per unit area can be calculated by counting the numberof the reactive inorganic fine particles (A) in a STEM photograph etc.of the depth-directional cross section of the hard coat layer, anddividing the counted number of particles by the area where the particlesare present.

By having the reactive inorganic fine particles (A) unevenly distributedat the surface region being the interface and its vicinity on the sideopposite to the transparent substrate film side of the hard coat layer,and having higher average particle number of the reactive inorganic fineparticles (A) than a region other than the surface region, the hardnessof the hard coat layer can be improved due to high hardness of thereactive inorganic fine particles (A) themselves. Further, due to unevendistribution of the crosslinking points of the reactive inorganic fineparticles (A) and the binder component (B), film strength can beimproved. By unevenly distributing the reactive inorganic fine particles(A), the hard coating performance of the surface of the hard coat layercan be significantly and efficiently increased in comparison with thecase having the same amount of the reactive inorganic fine particles (A)dispersed in the whole hard coat layer.

Moreover, in the hard coat film of the present invention, the reactiveinorganic fine particles (A) are unevenly distributed from the surfaceof the hard coat layer to a certain depth (skin layer), and the averageparticle number of the reactive inorganic fine particles (A) per unitarea of a thickness-directional cross section drastically decreases whenit is deeper than the above certain depth. By distributing the reactiveinorganic fine particles (A) so that the border of the region (skinlayer) where reactive inorganic fine particles (A) are unevenlydistributed is clear, the hard coating performance of the hard coatlayer can be effectively increased compared to the case that reactiveinorganic fine particles are unevenly distributed in a graded structurein which the density of the reactive inorganic fine particles graduallydecreases from the surface of the hard coat layer.

The thickness of the skin layer is preferably from the interface on theside opposite to the transparent substrate film side to the averageparticle diameter of the reactive inorganic fine particle (A) up totwice of the average particle diameter. By unevenly distributing thereactive inorganic fine particles (A) in a significantly limited narrowsurface region on the air interface side of the hard coat layer, thehard coating performance of the hard coat layer can be efficientlyincreased.

Also, to increase the effect of improving the hard coating performanceof the skin layer, it is preferable that the reactive inorganic fineparticles (A) are aggregated in the skin layer. Herein, “reactiveinorganic fine particles (A) are aggregated” means a state that adjacentreactive inorganic fine particles (A) are in contact with each other. Byincreasing uneven distribution of the reactive inorganic fine particles(A) in the skin layer, the hardness and film strength of the surface ofthe hard coat layer can be further improved.

If the average particle number of the reactive inorganic fine particles(A) per unit area of a thickness-directional cross section of the skinlayer is twice or more, more preferably three times or more, even morepreferably five times or more, than the average particle number of thereactive inorganic fine particles (A) per unit area of thethickness-directional cross section of the whole hard coat layerincluding the skin layer, the hard coating performance of the hard coatlayer can be sufficiently improved.

More specifically, it is preferable that the average particle number ofthe reactive inorganic fine particles (A) per unit area of thethickness-directional cross section of the skin layer is 2,000/μm² ormore, and the average particle number of the reactive inorganic fineparticles (A) per unit area of the thickness-directional cross sectionof the whole hard coat layer is 2,000/μm² or less. From the viewpoint ofthe hard coating performance of the hard coat layer, particularly, it ismore preferable that the average particle number of the reactiveinorganic fine particles (A) per unit area of a thickness-directionalcross section of the skin layer is 3,000/μm² or more.

In the hard coat film, the hard coat layer is always disposed on thesurface at the side of an observer. Herein, “the side of an observer” inthe present invention means the surface which is faced to the observerwhen the hard coat film of the present invention is disposed on thefront face of an image display. “Display side” in the present inventionmeans the surface which is faced to an image display body when the hardcoat film of the present invention is disposed on the front face of theimage display.

In the hard coat film 10 shown in FIG. 1, the hard coat layer isdirectly disposed on the transparent substrate film, but the hard coatlayer may be disposed on the transparent substrate film via otherlayers. The hard coat layer is not limited to a single layer and may bea laminated structure having two or more layers. The specific laminatedstructure will be described hereinafter.

Hereinafter, the hard coat film of the present invention will beexplained in detail.

Herein, “(meth)acryloyl” means acryloyl and/or meth acryloyl,“(meth)acrylate” means acrylate and/or methacrylate, and “(meth)acryl”means acryl and/or methacryl. Also, herein, “light” includes not onlyelectromagnetic waves having a wavelength in the visible or nonvisibleregion but also particle beams (e.g. electron beams) and radiation (ageneral term for electromagnetic waves and particle beams) or ionizingradiation.

Also, herein, the reactive functional group (a) and the reactivefunctional group (b) include a photocurable functional group and aheat-curable functional group. The photocurable functional group means afunctional group which can proceed a polymerization reaction, acrosslinking reaction, etc. by light radiation and cure a coating layer.The examples include photocurable functional groups which proceed areaction by polymerization reaction such as photo-radicalpolymerization, photo-cationic polymerization and photo-anionicpolymerization, and by a reaction form including addition polymerizationand condensation polymerization via photodimerization. Also, herein, theheat-curable functional group means a functional group which can cure acoating layer by proceeding polymerization reaction, crosslinkingreaction, etc. of the same kind of functional groups or betweendifferent kinds of functional groups by heating. The examples include ahydroxy group, a carboxyl group, an amino group, an epoxy group and anisocyanate group.

As the reactive functional group used in the present invention, apolymerizable unsaturated group, preferably a photocurable unsaturatedgroup, even more preferably ionizing radiation-curable unsaturatedgroup, is suitably used particularly from the viewpoint of improvementof hardness of a cured film. Specific examples thereof include ethylenedouble bonds such as a (meth)acryloyl group, a vinyl group and an allylgroup, and an epoxy group.

<Transparent Substrate Film>

The material of the transparent substrate film is not particularlylimited, but any material generally used for a hard coat film may beused. The examples include materials mainly comprising celluloseacylate, a cycloolefin polymer, an acrylate-based polymer or polyester.The “mainly comprising” used herein means a component that has thehighest content rate among the components of the transparent substratefilm.

Specific examples of the cellulose acylate include cellulose triacetate,cellulose diacetate and cellulose acetate butyrate.

Examples of the cycloolefin polymer include norbornene polymers,monocyclic olefin polymers, cyclic conjugated diene polymers and vinylalicyclic hydrocarbon polymer resins. More specifically, there may beZEONEX and ZEONOR (product names; manufactured by ZEON CORPORATION;norbornene resins), SUMILITE FS 1700 (product name; manufactured bySUMITOMO BAKELITE CO., LTD.), ARTON (product name; manufactured by JSRCorporation; modified norbornene resin), APEL (product name;manufactured by MITSUI CHEMICALS, INC.; cycloolefin copolymer), Topas(product name; manufactured by Ticona; cycloolefin copolymer), and OZ1000 Series of OPTOREZ (product name; manufactured by Hitachi ChemicalCompany, Ltd.; alicyclic acrylic resin).

Specific examples of the acrylate-based polymer includepoly(methyl(meth)acrylate), poly(ethyl(meth)acrylate) andmethyl(meth)acrylate-butyl(meth)acrylate copolymers. Herein,(meth)acrylate means acrylate, methacrylate or a mixed system of both.

Specific examples of the polyester include polyethylene terephthalateand polyethylene naphthalate.

In the present invention, the transparent substrate film 2 is a thinflexible film-like body. The thickness is from 20 μm to 300 μm,preferably the upper limit is 200 μm or less and the lower limit is 30μm or more. The transparent substrate film 2 may have paint called ananchor agent or a primer preliminarily applied besides physicaltreatment such as corona discharge treatment, oxidation treatment or thelike upon forming the hard coat layer 1 on the transparent substratefilm 2 for improvement of adhesion.

<Hard Coat Layer>

The hard coat layer is an essential layer in the hard coat film of thepresent invention, and provided on the surface on the side of anobserver. The hard coat layer may be constituted with one layer only ortwo or more layers.

In the present invention, the hard coat layer formed preliminarily maybe layered on the surface of the transparent substrate film, etc.

The hard coat layer of the hard coat film of the present invention isformed by containing the reactive inorganic fine particles (A) forincreasing hard coating performance and components including the bindercomponent (B) for imparting adhesion to the substrate and adjacentlayers as an essential component and forming a matrix of the hard coatlayer after curing the curable binder system, and further if necessary,additives such as an anti-static agent and a leveling agent, and aninorganic filler for adjustment of refractive index, prevention ofcrosslinking concentration or imparting high indentation strength. Thehard coat layer is provided on the transparent substrate film directlyor via other layers.

The “hard coat layer” generally means a layer which can obtain ahardness of “H” or more on the pencil hardness test defined in JISK5600-5-4 (1999). It is preferable that the surface of the hard coatlayer 1 for the first aspect of the invention has a hardness of “3H” ormore on the pencil hardness test.

In the hard coat film of the first aspect of the invention, it isgenerally preferable that the layer thickness of the hard coat layer is2 to 30 μm, more preferably 5 to 20 μm.

Hereinafter, constituent materials of the hard coat layer will beexplained.

<Reactive Inorganic Fine Particles (A)>

The inorganic fine particles are generally contained in the hard coatlayer to maintain transparency and improve hard coating performance.Also, by allowing inorganic fine particles having cross-linkingreactivity and a curable binder to crosslinkingly react to form acrosslinking structure, the hard coating performance can be furtherimproved. The reactive inorganic fine particle (A) means an inorganicfine particle, the surface of which has the reactive functional group(a) introduced by the organic component, which covers at least a part ofthe surface of inorganic fine particle being a core. The reactiveinorganic fine particle (A) includes ones having two or more inorganicfine particles being cores per reactive inorganic fine particle (A).

By decreasing the particle size of the reactive inorganic fine particles(A), the crosslinking point in the matrix can be increased with respectto the content.

The hard coat layer of the present invention contains the above reactiveinorganic fine particles (A) for the purpose of significantly improvinghardness to have sufficient abrasion resistance. The reactive inorganicfine particles (A) may be ones imparting further functions to the hardcoat layer, and can be selected according to purpose.

Examples of the inorganic fine particles include metal oxide fineparticles of silica (SiO₂), aluminum oxide, zirconia, titania, zincoxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO),antimony oxide and cerium oxide; and metal fluoride fine particles ofmagnesium fluoride and sodium fluoride. Also, metal fine particles,metal sulfide fine particles, metal nitride fine particles, etc. may beused.

From the viewpoint of high hardness, silica and aluminum oxide arepreferable. Also, for making a layer having a relatively high refractiveindex, fine particles increasing refractive index upon forming a filmsuch as zirconia, titania or antimony oxide may be accordingly selectedand used. Similarly, for making a layer having a relatively lowrefractive index, fine particles which lower refractive index uponforming a film including fluoride fine particles such as magnesiumfluoride, sodium fluoride and hollow silica fine particles can beaccordingly selected and used. Further, to impart anti-staticproperties, electrical conductivity, indium tin oxide (ITO), tin oxide,etc. can be accordingly selected and used, which may be used alone or incombination of two or more kinds.

In the hard coat film of the present invention, in the case of usinghollow reactive inorganic fine particles (A) such as hollow silica orreactive inorganic fine particles (A) having a porous structure,acceleration of uneven distribution of the reactive inorganic fineparticles (A) toward the air interface side can be expected due to theapparent specific gravity (mass per unit volume, being averagedincluding the hollow parts), however, hollow or porous inorganic fineparticles has lower hardness than non-hollow inorganic fine particlesdue to its structure. Therefore, in the present invention, it ispreferable that typically by using non-hollow reactive inorganic fineparticles (A), the hardness is ensured, and uneven distribution of thereactive inorganic fine particles (A) is accelerated by controlling itsparticle diameter.

On the surface of the inorganic fine particles, groups which generallycannot exist in the form in the inorganic fine particles. Such groups onthe surface are generally relatively reactive functional groups. Theexamples include a hydroxyl group and an oxy group in the case of metaloxide, a thiol group and a thio group in the case of metal sulfide, andan amino group, an amide group and an imide group in the case ofnitride.

The reactive inorganic fine particles (A) used in the present inventionhave at least a part of the surface of which covered by the organiccomponent, and have reactive functional groups (a) which are introducedby the organic component on the surface. Herein, the organic componentis a component containing carbon. Also, examples of the embodiment inwhich at least apart of the surface is covered by the organic componentinclude an embodiment in which a compound containing organic componentsuch as a silane coupling agent is reacted with a hydroxyl group presenton the surface of the metal oxide fine particles, an embodiment in whichthe organic component is bonded to a part of the surface, an embodimentin which the organic component is attached to a hydroxyl group presenton the surface of metal oxide fine particles by interaction such ashydrogen bond, and an embodiment in which one or more inorganic fineparticles are contained in the polymer particles.

It is preferable that almost all surface of the particle is covered bythe organic component from the viewpoint of preventing aggregation ofinorganic fine particles from each other, and improving harness of thefilm by introducing many reactive functional groups on the surface ofthe inorganic fine particles. Due to these viewpoints, it is preferablethat the organic component covering the reactive inorganic fine particle(A) is contained in the reactive inorganic fine particles (A) by1.00×10⁻³ g/m² or more per unit area of the inorganic fine particlesbefore being covered.

In the embodiment that the organic component is attached or connected tothe surface of the inorganic fine particle, the organic componentcovering the reactive inorganic fine particle (A) is contained in thereactive inorganic fine particles (A) more preferably by 2.00×10⁻³ g/m²or more, even more preferably by 3.50×10⁻³ g/m² or more, per unit areaof the inorganic fine particle before being covered.

In the embodiment that the inorganic fine particles are contained in thepolymer particles, the organic component covering the reactive inorganicfine particle (A) is contained in the reactive inorganic fine particles(A) more preferably by 3.50×10⁻³ g/m² or more, even more preferably by5.50×10⁻³ g/m² or more, per unit area of the inorganic fine particlebefore being covered.

The ratio of the organic component covering the reactive inorganic fineparticle (A) can be generally obtained by, for example,thermogravimetric analysis in air from room temperature generally to800° C. as a constant mass value of percentage of weight reduction whendried powder is completely burned in air.

The amount of the organic component per unit area is obtained by thefollowing method. Firstly, a value in which the weight of the organiccomponent is divided with the weight of the inorganic component (theweight of the organic component/the weight of the inorganic component)is measured by differential thermogravimetric analysis (TG-DTA). Next,the volume of the whole inorganic component is calculated from theweight of the inorganic component and the specific gravity of theinorganic fine particles. Also, assuming that the inorganic fineparticles before being covered are in spherical forms, the volume perinorganic fine particle before being covered and surface area arecalculated from the average particle diameter of the inorganic fineparticles before being covered. Next, the number of the inorganic fineparticles before being covered is calculated by dividing the area ofwhole inorganic component by the volume per inorganic fine particlebefore being covered. Further, the amount of the organic component perreactive inorganic fine particle (A) is calculated by dividing theweight of the organic component by the number of inorganic fineparticles. Finally, the amount of the organic component per unit area ofthe inorganic fine particle before being covered is calculated bydividing the weight of the organic component per reactive inorganic fineparticle (A) by the surface area per inorganic fine particle beforebeing covered.

The average particle diameter of the reactive inorganic fine particles(A) used for the first aspect of the invention is from 5 nm to 30 nm.The present invention uses such reactive inorganic fine particles (A)having a relatively small particle diameter. Thereby, unevendistribution of the reactive inorganic fine particles (A) in the hardcoat layer toward a certain region (the surface region being aninterface and its vicinity on the side opposite to the transparentsubstrate film side) is enhanced, and the improvement of the hardcoating performance of the hard coat layer by the reactive inorganicfine particles (A) can be attained.

Since the reactive inorganic fine particle (A) having a small particlediameter, i.e. the average particle diameter in the above range, has alarge specific surface area, the force of phase separation increases inthe curable resin composition due to action based on compatibility witha binder component. As a result, in the curable resin compositionapplied on the transparent substrate film, a part of the reactiveinorganic fine particles (A) naturally diffuse toward the air interfaceside, and are unevenly distributed.

As described above, the hard coat film of the first aspect of theinvention accelerates uneven distribution of the reactive inorganic fineparticles (A), and can attain improvement of the hard coatingperformance of the hard coat layer by utilizing increase of phaseseparation ability and diffuseness due to small particle diameter of thereactive inorganic fine particles (A).

The average particle diameter of the reactive inorganic fine particles(A) used for the first aspect of the invention is preferably from 5 nmto 30 nm, more preferably from 5 nm to 25 nm, from the viewpoint ofhardness and excellent formation of the skin layer.

By setting the average particle diameter of the reactive inorganic fineparticles (A) to be 5 nm or more, the hard coating performance of thehard coat layer can be sufficiently improved. On the other hand, byusing the reactive inorganic fine particle (A) having an averageparticle diameter of 30 nm or less, uneven distribution of the reactiveinorganic fine particles (A) can be sufficiently enhanced, andsufficient effect of improving the hard coating performance due touneven distribution of the reactive inorganic fine particles (A). Also,since the reactive inorganic fine particle (A) having an averageparticle diameter of 30 nm or less has a large specific surface area,there is an advantage that the crosslinking point in the matrix can beincreased, and a hard coat layer having high film strength can beobtained.

Also, from the viewpoint of significantly improving hardness withoutdeteriorating transparency, and by maintaining the recovery rate of thehard coat layer when only a resin is used, it is preferable that thereactive inorganic fine particle (A) has narrow particle sizedistribution, and is monodispersed.

Herein, the average particle diameter can be obtained by observing across-section TEM photography of a hard coat film formed using thereactive inorganic fine particle (A), measuring particle diameters ofreactive inorganic fine particles (A), and calculating an average valuetherefrom, or by preparing a sol comprising the reactive inorganic fineparticles (A) dispersed in a solvent, and calculating 50% averageparticle diameter in the sol by means of, for example, Nanotrac (productname; manufactured by Nikkiso Co., Ltd.) or a particle size analyzer.

As the reactive functional group (a) of the reactive inorganic fineparticle (A), a polymerizable unsaturated group is suitably usedparticularly from the viewpoint of improving hardness of a cured film.Preferred are photocurable unsaturated groups, and particularlypreferred are ionizing radiation-curable unsaturated groups. Specificexamples thereof include an ethylenic double bond such as a(meth)acryloyl group, vinyl group and allyl group, and an epoxy group.

As the method of preparing the reactive inorganic fine particle (A) inwhich at least a part of the surface is covered with an organiccomponent and each particle has the reactive functional group (a)introduced onto the covered surface by the organic component, aconventionally-known method may be accordingly selected for usedepending on the kind of the inorganic fine particle and reactivefunctional group (a) to be introduced.

Particularly in the present invention, it is preferred to accordinglyselect any of the following inorganic fine particles (i) and (ii) foruse, from the viewpoint of containing the organic component covering thereactive inorganic fine particle (A) in the reactive inorganic fineparticle (A) by 1.00×10⁻³ g/m² or more per unit area of the inorganicfine particle before being covered, preventing aggregation of theinorganic fine particles and increasing the hardness of a film:

(i) inorganic fine particles having a reactive functional group on thesurface obtained by dispersing inorganic fine particles in water and/oran organic solvent serving as a dispersion medium in the presence of oneor more kinds of surface modification compounds having a molecularweight of 500 or less selected from the group consisting of saturated orunsaturated carboxylic acid, acid anhydride, acid chloride, ester andacid amide corresponding to the carboxylic acid, amino acid, imine,nitrile, isonitrile, an epoxy compound, amine, a β-dicarbonyl compound,silane and a metallic compound having a functional group; and

(ii) inorganic fine particles having a reactive functional group on thesurface obtained by bounding a compound containing the reactivefunctional group (a) being introduced on the surface of the reactiveinorganic fine particle (A), a group represented by the followingchemical formula (1), and a silanol group or a group producing thesilanol group by hydrolysis, with metal oxide fine particles:

-Q¹-C(=Q²)-NH—  Chemical Formula (1)

wherein Q¹ is NH, O (oxygen atom) or S (sulfur atom); and Q² is O or S.

Hereinafter, the reactive inorganic fine particles (A) which aresuitably used in the present invention will be described in order.

(i) Inorganic fine particles having a reactive functional group on thesurface, in which particles are obtained by dispersing inorganic fineparticles in water and/or an organic solvent serving as a dispersionmedium, in the presence of one or more kinds of surface modificationcompounds which have a molecular weight of 500 or less and are selectedfrom the group consisting of a saturated or unsaturated carboxylic acid,an acid anhydride, acid chloride, ester and acid amide corresponding tothe carboxylic acid, an amino acid, an imine, a nitrile, an isonitrile,an epoxy compound, an amine, a β-dicarbonyl compound, silane and ametallic compound having functional groups.

Use of the reactive inorganic fine particles (A) (i) is advantageous inthat the film strength can be increased even if the content of theorganic component is small.

The surface modification compound used for the reactive inorganic fineparticle (A) (i) has a functional group that can chemically bound to,upon dispersion, a group present on the surface of the inorganic fineparticle, such as a carboxyl group, acid anhydride group, acid chloridegroup, acid amide group, ester group, imino group, nitrile group,isonitrile group, hydroxyl group, thiol group, epoxy group, primary,secondary or tertiary amino group, Si—OH group, hydrolyzable residue ofsilane, or C—H acid group such as a β-dicarbonyl compound. The chemicalbonding herein preferably includes covalent bonding, ionic bonding orcoordination bonding, and hydrogen bonding. Coordination bonding isconsidered to be complex forming. For example, an acid-base reactionaccording to the Brønsted or Lewis definition, complex formation oresterification occurs between the functional groups of the surfacemodification compound and the groups present on the surface of theinorganic fine particles. The surface modification compound used for thereactive inorganic fine particle (A) (i) may be one kind of componentsolely or a mixture of two or more kinds of components.

In addition to at least one functional group (hereinafter referred to asfirst functional group) that can participate in chemical bonding withthe groups that are present on the surface of the inorganic fineparticles, the surface modification compound normally has molecularresidues that impart, after being bound to the surface modificationcompound, a new property to the inorganic fine particles via thefunctional group. The molecular residues or a part of the molecularresidues are hydrophobic or hydrophilic and, for example, can stabilize,integrate or activate the inorganic fine particles.

Examples of the hydrophobic molecular residue include an alkyl, aryl,alkaryl, and aralkyl group, all of which induce inactivation orrepulsion. Examples of the hydrophilic group include a hydroxy group,alkoxy group and polyester group.

The reactive functional group (a), which is introduced to the surface ofthe reactive inorganic fine particle (A) so that the reactive inorganicfine particle (A) can react with the binder component (B) hereinafterdescribed, is appropriately selected according to the reactivefunctional group (b) of the binder component (B). As the reactivefunctional group (a), a polymerizable unsaturated group is suitablyused, and a photocurable unsaturated group is more preferable, anionizing radiation-curable unsaturated group is even more preferable.The specific examples include ethylenically unsaturated bonds(particularly, ethylenic double bonds) such as a (meth)acryloyl group, avinyl group and an allyl group, and an epoxy group.

In the case where the reactive functional groups (a) which are reactivewith the binder component (B) are contained in the molecular residues ofthe surface modification compound, the reactive functional groups (a)that are reactive with the binder component (B) can be introduced ontothe surface of the reactive inorganic fine particles (A) (i) by allowingthe first functional group(s) contained in the surface modificationcompound to react with the surface of the inorganic fine particles. Forexample, a surface modification compound having polymerizableunsaturated groups besides the first functional group(s) may bementioned as a suitable one.

Meanwhile, by allowing a second reactive functional group to becontained in the molecular residues of the surface modification compoundand by the aid of the second reactive functional group, the reactivefunctional group (a) reactive with the binder component (B) may beintroduced onto the surface of the reactive inorganic fine particle (A)(i). For example, it is preferable to introduce the reactive functionalgroup (a) reactive with the binder component (B) in such a manner that agroup capable of hydrogen bonding (hydrogen bond-forming group) such asa hydroxyl group or oxy group is introduced as the second reactivefunctional group so that the hydrogen bond-forming group is introducedonto the surface of the fine particle and further reacts with a hydrogenbond-forming group of a different surface modification compound. Thatis, as a suitable example, there may be mentioned use of a compoundhaving a hydrogen bond-forming group in combination with a compoundhaving the reactive functional group (a) reactive with the bindercomponent (B) (such as a polymerizable unsaturated group) and a hydrogenbond-forming group as the surface modification compound.

Specific examples of the hydrogen bond-forming group include functionalgroups such as a hydroxyl group, carboxyl group, epoxy group, glycidylgroup and amide group, and one capable of having an amide bond. Theamide bond herein refers to one containing —NHC(O) or >NC(O)— in thebinding unit thereof. As the hydrogen bond-forming group used in thesurface modification compound of the present invention, a carboxylgroup, hydroxyl group or amide group is particularly preferred.

The surface modification compound used for the reactive inorganic fineparticle (A) (i) preferably has a molecular weight of 500 or less, morepreferably 400 or less, even more preferably 200 or less. Because ofhaving such a low molecular weight, the surface modification compound ispresumed to be able to rapidly cover the surface of the inorganic fineparticles, so that the inorganic fine particles are prevented fromaggregation.

The surface modification compound used for the reactive inorganic fineparticle (A) (i) is preferably liquid in the reaction condition forsurface modification, and it is preferable that the compound is solubleor at least can be emulsified in a dispersion medium. Particularly, itis preferable that the surface modification compound can be dissolved ina dispersion medium to exist as molecules or molecular ions disperseduniformly in the dispersion medium.

The saturated or unsaturated carboxylic acid preferably has 1 to 24carbon atoms. Examples thereof include formic acid, acetic acid,propionic acid, butyric acid, valeric acid, caproic acid, acrylic acid,methacrylic acid, crotonic acid, citric acid, adipic acid, succinicacid, glutaric acid, oxalic acid, maleic acid, fumaric acid, itaconicacid and stearic acid, and acid anhydrides, chlorides, esters and amidescorresponding thereto, such as caprolactam. The carboxylic acid includesone with a carbon chain blocked by a O-group, S-group or NH-group.Particularly preferable examples include ether carboxylic acid such asmonoether carboxylic acid and polyether carboxylic acid, correspondingacid anhydrides thereof, esters and amides (e.g. methoxyacetic acid,3,6-dioxa hepatanoate and 3,6,9-trioxa decanoate). Further, it ispossible to introduce polymerizable unsaturated groups by using anunsaturated carboxylic acid.

An example of preferred amine is one having the chemical formulaQ_(3-n)NH_(n) (n=0, 1 or 2), wherein the residue Q independentlyrepresents an alkyl (such as methyl, ethyl, n-propyl, i-propyl andbutyl) having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms,even more preferably 1 to 4 carbon atoms, and an aryl, alkaryl oraralkyl (such as phenyl, naphthyl, tolyl and benzyl) having 6 to 24carbon atoms. Also, an example of preferred amine is polyalkyleneamine.Specific examples thereof include methylamine, dimethylamine,trimethylamine, ethylamine, aniline, N-methylaniline, diphenylamine,triphenylamine, toluidine, ethylenediamine and diethylenetriamine.

The β-dicarbonyl compound is preferably one having 4 to 12 carbon atoms,particularly preferably 5 to 8 carbon atoms, such as diketone(acetylacetone, etc.), 2,3-hexanedione, 3,5-heptanedione, acetoaceticacid, acetoacetic acid-C₁-C₄-alkyl ester (acetoacetic acid ethyl ester,etc.), diacetyl and acetonylacetone.

Examples of the amino acid include β-alanine, glycine, valine, aminocaproic acid, leucine and isoleucine.

Preferred silane is hydrolyzable organosilane having at least onehydrolyzable group or hydroxy group and at least one nonhydrolyzableresidue. Examples of the hydrolyzable group include a halogen, alkoxygroup and acyloxy group. As the nonhydrolyzable residues,nonhydrolyzable residues having the reactive functional groups (a)and/or having no reactive functional groups (a) is used.

The silane used herein is not particularly limited and may be, forexample, CH₂═CHSi(OOCCH₃)₃, CH₂═CHSiCl₃, CH₂═CHSi (OC₂H₅)₃,CH₂═CH—Si(OC₂H₄OCH₃)₃, CH₂|CH—CH₂—Si(OC₂H₅)₃, CH₂═CH—CH₂—Si(OOCCH₃)₃,γ-glycidyloxypropyltrimethoxysilane (GPTS),γ-glycidyloxypropyldimethylchlorosilane, 3-aminopropyltrimethoxysilane(APTS), 3-aminopropyltriethoxysilane (APTES),N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,N—[N′-(2′-aminoethyl)-2-aminoethyl]-3-aminopropyltrimethoxy silane,hydroxymethyltrimethoxysilane,2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane,bis-(hydroxyethyl)-3-aminopropyltriethoxysilane,N-hydroxyethyl-N-methylaminopropyltriethoxysilane,3-(meth)acryloxypropyltriethoxysilane and3-(meth)acryloxypropyltrimethoxysilane.

As the metallic compound having functional groups, there may bementioned a metallic compound of a metal M selected from the primarygroups III to V and/or the secondary groups II to IV of the periodicaltable of the elements. Examples of the metallic compound includezirconium alkoxide and titanium alkoxide, and M(OR)₄ (M=Ti or Zr)wherein a part of the OR group is replaced with a β-dicarbonyl compoundor a complexing agent such as monocarboxylic acid. In the case of usinga compound having a polymerizable unsaturated group (such as methacrylicacid) as the complexing agent, it is possible to introduce polymerizableunsaturated groups.

As the dispersion medium, water and/or an organic solvent is suitablyused. A particularly preferred dispersion medium is distilled (pure)water. As the organic solvent, a polar solvent, nonpolar solvent oraprotic solvent is preferred. Examples thereof include alcohols such asaliphatic alcohols having 1 to 6 carbon atoms (in particular, methanol,ethanol, n-(normal) and i-(iso) propanol and butanol); ketones such asacetone and butanone; esters such as ethyl acetate; ethers such asdiethyl ether, tetrahydrofuran and tetrahydropyran; amides such asdimethylacetamide and dimethylformamide; sulfoxides and sulfones such assulfolane and dimethylsulfoxide; and aliphatic (optionally halogenated)hydrocarbons such as pentane, hexane and cyclohexane. These dispersionmedia may be used as a mixture.

The dispersion medium preferably has a boiling point at which it can beeasily removed by distillation (optionally under reduced pressure).Preferred as the dispersion medium is a solvent having a boiling pointof 200° C. or less, more preferably 150° C. or less.

In preparation of the reactive inorganic fine particles (A) (i), theconcentration of the dispersion medium is normally from 40 to 90 wt %,preferably from 50 to 80 wt %, more preferably from 55 to 75 wt %. Therest of the dispersion is composed of untreated inorganic fine particlesand the above surface modification compound. Herein, the weight ratio ofthe inorganic fine particles to the surface modified compound ispreferably from 100:1 to 4:1, more preferably from 50:1 to 8:1, stillmore preferably from 25:1 to 10:1.

Preparation of the reactive inorganic fine particles (A) (i) ispreferably carried out at a temperature from room temperature (about 20°C.) to the boiling point of the dispersion medium. The dispersiontemperature is particularly preferably from 50 to 100° C. The dispersiontime particularly depends on the kind of raw materials used, and isnormally few hours such as 1 to 24 hours.

An embodiment in which, upon preparing the reactive inorganic fineparticles (A) (i), the inorganic fine particles are subjected tomechanical reaction pulverization in a dispersion media containing thesurface modification compound, and the surface modification compoundhave at least partially a chemical bond with pulverized colloidalinorganic fine particles, may be used.

The mechanical pulverization is performed generally by, for example, amill, kneader, cylinder mill or high-speed disperser. Examples ofpulverizers suitable for mechanical pulverization include homogenizers,turbo stirrers, mills having separate pulverization tool such as a ballmill, rod mill, dram mill, cone mill, tube mill, autogenous mill,planetary mill, vibration mill and stirrer mill, heavy-roller kneaders,colloid mills and cylinder mills. Among the above, a particularlypreferred mill is an agitation ball mill having a motion stirrer andpulverization ball as pulverization means.

Pulverization with pulverization and homogenizing are preferablyperformed at room temperature. The time is adjusted according to thekind of mixing and a pulverizer being used.

(ii) Inorganic fine particles having a reactive functional group on thesurface, in which particles are obtained by bonding metal oxide fineparticles being inorganic fine particles that will be cores to acompound containing reactive functional groups (a) that will beintroduced onto the inorganic fine particles, groups represented by thefollowing chemical formula (1), and silanol groups or groups that areable to become silanol groups by hydrolysis:

-Q¹-C(=Q²)-NH—  Chemical Formula (1)

wherein Q¹ is NH, O (oxygen atom) or S (sulfur atom); and Q² is O or S.

Use of the reactive inorganic fine particle (A) (ii) is advantageous inthat the amount of the organic component is increased, so that thedispersibility of the reactive inorganic fine particle (A) and the filmstrength are further increased.

Firstly, a compound having the reactive functional group (a), which isrequired to be introduced onto the inorganic fine particle, the grouprepresented by the above chemical formula (1), and a silanol group or agroup that is able to become a silanol group by hydrolysis will bedescribed. Hereinafter, this compound may be referred to as a reactivefunctional group modified hydrolyzable silane.

In the reactive functional group modified hydrolyzable silane, thereactive functional group (a), which is required to be introduced ontothe reactive inorganic fine particle, is not particularly limited if itis appropriately selected so as to react with the reactive functionalgroup (b) of the binder component (B). The reactive functional groupmodified hydrolyzable silane is suitable to introduce theabove-mentioned polymerizable unsaturated group.

In the reactive functional group modified hydrolyzable silane, examplesof the [-Q¹-C(=Q²)-NH—] moiety of the group represented by the abovechemical formula (1) include the following six kinds of [—O—C(═O)—NH—],[—O—C(═S)—NH—], [—S—C(═O)—NH—], [—NH—C(═O)—NH—], [—NH—C(═S)—NH—] and[—S—C(═S)—NH—].

They may be used solely or in combination of two or more kinds.Particularly from the viewpoint of thermal stability, it is preferableto use the [—O—C(═O)—NH—] group in combination with at least one of the[—O—C(═S)—NH—] and [—S—C(═O)—NH—] groups. The group represented by theabove chemical formula (1), [-Q¹-C(=Q²)-NH—], causes appropriateintermolecular cohesion by hydrogen bonding. When a cured product isformed, it is considered possible to impart properties such as excellentmechanical strength, adhesion to the substrate and heat resistance tothe product.

Examples of the groups that are able to become silanol groups byhydrolysis include groups having an alkoxy group, aryloxy group, acetoxygroup, amino group, halogen atom or the like on a silicon atom thereof.Preferred is an alkoxysilyl group or aryloxysilyl group. The silanolgroups or groups that are able to become silanol groups by hydrolysiscan be combined to the metal oxide fine particles by a condensationreaction that occurs after a condensation reaction or hydrolysis.

A preferred specific example of the reactive functional group modifiedhydrolyzable silane may be compounds represented by the followingchemical formula (2).

In the chemical formula (2), R^(a) and R^(b) may be the same ordifferent from each other, and are a hydrogen atom or a C₁-C₈ alkyl oraryl group such as a methyl, ethyl, propyl, butyl, octyl, phenyl andxylyl group; and m is 1, 2 or 3.

Examples of the group represented by [(R^(a)O)_(m)R^(b) _(3-m)Si—]include a trimethoxysilyl group, triethoxysilyl group, triphenoxysilylgroup, methyldimethoxysilyl group and dimethylmethoxysilyl group. Amongthese groups, preferred are trimethoxysilyl and triethoxysilyl groups.

In the chemical formula (2), R^(c) is a C₁-C₁₂ divalent organic grouphaving an aliphatic or aromatic structure, and may contain a chain,branched or cyclic structure. Examples of such an organic group includemethylene, ethylene, propylene, butylene, hexamethylene, cyclohexylene,phenylene, xylylene and dodecamethylene. Among the above, preferred aremethylene, propylene, cyclohexylene and phenylene.

Also, R^(d) is a divalent organic group and is normally selected fromdivalent organic groups having a molecular weight of 14 to 10,000,preferably a molecular weight of 76 to 500. The examples include a chainpolyalkylene group such as hexamethylene, octamethylene anddodecamethylene; an alicyclic or polycyclic divalent organic group suchas cyclohexylene and norbornylene; a divalent aromatic group such asphenylene, naphthylene, biphenylene and polyphenylene; and alkylgroup-substituted derivatives and aryl group-substituted derivativesthereof. These divalent organic groups may contain an atom group thatcontains an element other than carbon and hydrogen atom, and may furthercontain a polyether bond, a polyester bond, a polyamide bond, apolycarbonate bond, and a group represented by the chemical formula (1).

R^(e) is a (n+1)-valent organic group and is preferably selected from achain, branched or cyclic saturated or unsaturated hydrocarbon group.

Y′ denotes a monovalent organic group having reactive functional groups(a) and may be the above-mentioned reactive functional groups. In thecase of selecting the reactive functional groups (a) from polymerizableunsaturated groups, the examples include a (meth)acryloyl(oxy) group,vinyl(oxy) group, propenyl(oxy) group, butadienyl(oxy) group,styryl(oxy) group, ethinyl(oxy) group, cinnamoyl(oxy) group, maleategroup and (meth)acrylamide group. Preferably, n is a positive integer of1 to 20, more preferably 1 to 10, even more preferably 1 to 5.

Synthesis of the reactive functional group modified hydrolyzable silaneused in the present invention may be performed by the method disclosedin, for example, JP-A No. 9-100111. That is, for example, ifintroduction of polymerizable unsaturated groups is required, thesynthesis may be performed by: (I) addition reaction betweenmercaptoalkoxysilane, a polyisocyanate compound and an active hydrogengroup-containing polymerizable unsaturated compound reactive with anisocyanate group. The synthesis may be also performed by (II) directreaction between a compound having an alkoxysilyl group and isocyanategroup in a molecule thereof and an active hydrogen group-containingpolymerizable unsaturated compound. Furthermore, the reactive,hydrolyzable, functional group modification silane may be directlysynthesized by (III) addition reaction between a compound having apolymerizable unsaturated group and isocyanate group in a moleculethereof and mercaptoalkoxysilane or aminosilane.

Examples of mercaptoalkoxysilane suitably used includemercaptopropyltrimethoxysilane and mercaptopropyltriethoxysilane.

Examples of the polyisocyanate compound suitably used include2,4-tolylene diisocyanate, isophoronediisocyanate, xylenediisocyanate,methylenebis(4-cyclohexyl isocyanateisocyanate) and 1,3-bis(methylisocyanate)cyclohexane.

Examples of the active hydrogen group-containing polymerizableunsaturated compound include 2-hydroxyethyl (meth)acrylate,2-hydroxypropyl(meth)acrylate, trimethylolpropane di(meth)acrylate,pentaerythritol tri(meth)acrylate and dipentaerythritolpenta(meth)acrylate. Also, compounds obtained by addition reactionbetween a glycidyl group-containing compound such as alkyl glycidylether, allyl glycidyl ether or glycidyl(meth)acrylate and (meth)acrylicacid.

In the production of the reactive inorganic fine particle (A) (ii), amethod may be selected from the following: a method in which after thereactive functional group modified hydrolyzable silane is separatelyhydrolyzed, the resultant and the inorganic fine particles are mixedtogether, followed by heating and stirring; a method in which thereactive functional group modified hydrolyzable silane is hydrolyzed inthe presence of the inorganic fine particles; and a method in which asurface treatment is performed on the inorganic fine particles in thepresence of other component such as a polyvalent unsaturated organiccompound, a monovalent unsaturated organic compound and a radiationpolymerization initiator. Preferred is the method in which the reactivefunctional group modified hydrolyzable silane is hydrolyzed in thepresence of the inorganic fine particles. In the production of thereactive inorganic fine particle (A) (ii), the production temperature isnormally from 20° C. to 150° C., and the treating time is in the rangefrom 5 minutes to 24 hours.

To accelerate the hydrolysis reaction, acid, salt or base may be addedas a catalyst. Suitable examples of acid include organic acids andunsaturated organic acids; suitable examples of base include tertiaryamines and quaternary ammonium hydroxides. The added amount of acid,salt or base catalyst is from 0.001 to 1.0 wt %, preferably from 0.01 to0.1 wt %, with respect to the reactive functional group modifiedhydrolyzable silane.

In the first aspect of the invention, the reactive inorganic fineparticles (A) may be one not containing fluorine. Herein, the state of“not containing fluorine” is preferably the state in which the inorganicfine particles forming cores of reactive inorganic fine particles (A) isnot containing fluorine as well as the state in which the organiccomponent covering a part of the surface of the reactive inorganic fineparticles (A) is not containing fluorine. In the typical state, fluorineexists on the surface of the reactive inorganic fine particles (A).Specifically, it is not reactive inorganic fine particles (A) subjectedto surface treatment by a fluorine-containing surface preparation agent.

The reactive inorganic fine particles (A), the surface of which issubjected to surface treatment by the fluorine-containing surfacepreparation agent, easily causes phase separation and unevendistribution since the conformability to the curable resin compositionfor the hard coat layer further decreases. However, in the first aspectof the invention, since the average particle diameter of the reactiveinorganic fine particles (A) is set to 30 nm or less, aggregation of thereactive inorganic fine particles (A) due to uneven distribution of thereactive inorganic fine particles (A) is sufficiently enhanced. Thus,the present invention can form a hard coat layer in which the reactiveinorganic fine particles (A) are unevenly distributed at the surface onthe air interface side of the hard coat layer to the extent thatsufficient hard coating performance can be exhibited without the surfacetreatment using a fluorine-containing surface preparation agentperformed in Patent Literature 1.

It can be confirmed that the reactive inorganic fine particles (A) donot contain fluorine by the following method. That is, it can beconfirmed by cutting the hard coat film formed by the reactive inorganicfine particles (A) at, and detecting components contained in thereactive inorganic fine particles (A) by means of TOF-SIMS(Time-of-Flight secondary ion mass spectrograph such as one manufacturedby Ulvac-phi, Inc.). If the reactive inorganic fine particles (A) do notcontain fluorine, no fluorine atom is detected.

Also, as the reactive inorganic fine particles (A), powdery fineparticles containing no dispersion media may be used, but a solcomprising fine particles dispersed in a solvent is preferably usedsince the dispersion process is not necessary and the productivity ishigh.

Also, the content of the reactive inorganic fine particle (A) in thehard coat layer is preferably from 10 to 60 wt %, more preferably from20 to 40 wt %, with respect to the total solid content of the hard coatlayer (the total amount of the reactive inorganic fine particle (A) andthe constituents of the curable binder system).

By setting the lower limit to 10 wt % or more, the hardness of thesurface of the hard coat layer can be sufficiently improved. By settingthe upper limit to 60 wt % or less, decrease of film strength andadhesion due to increase of filling ratio of the reactive inorganic fineparticles (A) can be prevented.

<Curable Binder System>

Herein, the constituent components of the curable binder system refersto the binder component (B), and if necessary, curable binder componentsbesides the binder component (B), polymer components, and ones to bematrix components of the hard coat layer after being cured hereinafterdescribed such as a polymerization initiator.

(Binder Component (B))

The binder component (B) forming the hard coat layer has the reactivefunctional group (b) having cross-linkingly reactive with the reactivefunctional group (a) of the reactive inorganic fine particle (A). Thereactive functional group (a) of the reactive inorganic fine particle(A) and the reactive functional group (b) of the binder component (B)are crosslinked to form a mesh structure. It is preferable that thebinder component (B) has three or more reactive functional groups (b)per one molecule to obtain sufficient crosslinking ability. As thereactive functional group (b), a polymerizable unsaturated group issuitably used. The preferred examples include photocurable unsaturatedgroups, and particularly preferred are ionizing radiation-curableunsaturated groups. Specific examples thereof include an ethylenicallyunsaturated bond, particularly, an ethylene double bond such as a(meth)acryloyl group, vinyl group and allyl group, and an epoxy group.

The binder component (B) is preferably a curable organic resin, which ispreferably an optically-transparent resin that can let light throughwhen formed into a coating layer, and may be appropriately selected fromthree kinds of resins including ionizing radiation-curable resins whichare curable upon exposure to ionizing radiation typified by ultravioletlight or electron beams, a mixture of an ionizing radiation-curableresin and a solvent drying type resin (a resin which becomes a filmmerely by drying a solvent for adjusting solid content upon coating,e.g. thermoplastic resin), and heat-curable resin. The ionizingradiation-curable resins are preferred.

Specific examples of the ionizing radiation-curable resins includecompounds having a radically polymerizable functional group such as a(meth)acrylate group, e.g. (meth)acrylate-based oligomers, prepolymersand monomers.

More specific examples of (meth)acrylate-based oligomers and prepolymersinclude oligomers and prepolymers comprising (meth)acrylic ester ofpolyfunctional compound such as a polyester resin, a polyether resin, anacrylic resin, an epoxy resin, an urethane resin, an alkyd resin, aspiroacetal resin, a polybutadiene resin, a polythiol polyene resin andpolyol having relatively low molecular weight.

Example of the (meth)acrylate monomer, ethyl (meth)acrylate,ethylhexyl(meth)acrylate, hexanediol (meth)acrylate,hexanediol(meth)acrylate, tripropyleneglycol di(meth)acrylate,diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate,neopentyl glycol di(meth)acrylate, trimethylolpropane tir(meth)acrylate,pentaerythritol tri(meth)acrylate, and dipentaerythritolhexa(meth)acrylate.

Examples besides the (meth)acrylate compound include monofunctional andpolyfunctional monomers such as styrene, methyl styrene andN-vinylpyrrolidone, and compounds having cationic polymerizablefunctional group including oligomers and prepolymers such asbisphenol-type epoxy compounds, novolac-type epoxy compounds, aromaticvinyl ethers and aliphatic vinyl ethers.

When the ionizing radiation-curable resin is used as an UV-curableresin, a sensitizer can be added as a photopolymerization initiator orphotopolymerization accelerator.

Specific examples of the photopolymerization initiator for resin systemhaving a radically polymerizable functional group include acetophenones,benzophenones, Michler's benzoylbenzoates, α-amiroxym esters,tetramethylthiuram monosulfides, benzoins, benzoinmethylether,thioxanthones, propiophenones, benzyls, acylphosphine oxides and1-hydroxy-cyclohexyl-phenyl-ketone, which may be used alone or in amixture. 1-hydroxy-cyclohexyl-phenyl-ketone is available, for example,as Irgacure 184 (product name; manufactured by: Chiba SpecialtyChemicals, Inc.). Also, α-aminoalkylphenone is available, for example,as Irgacure 907 or 369 (product names).

For resin system having a cationic polymerizable functional group, anaromatic diazonium salt, an aromatic sulfonium salt, an aromaticiodonium salt, a metacelon compound or benzoinsulfonic acid ester isused alone or in a mixture as the photopolymerization initiator.

It is preferable that a photosensitizer is mixed and used, examples ofwhich include n-butylamine, triethylamine and poly-n-butylphosphine.

The added amount of the photopolymerization initiator is from 0.1 to 10parts by weight with respect to 100 parts by weight of ionizingradiation-curable composition.

As the solvent drying type resin mixed in the ionizing radiation-curableresin, there may be mainly a thermoplastic resin. A thermoplastic resingenerally exemplified can be utilized. By adding the solvent drying typeresin, coating defect on a coated surface can be effectively prevented.Specific preferable examples of the thermoplastic resin includestyrene-based resins, (meth)acrylic resins, organic acid vinylester-based resins, vinyl ether-based resins, halogen-containing resins,olefin-based resins (including cycloaliphatic olefin-based resins),polycarbonate-based resins, polyester-based resins, polyamide-basedresins, thermoplastic polyurethane resins, polysulfone-based resins(e.g. polyethersulfone and polysulfone), polyphenylene ether-basedresins (e.g. a polymer of 2,6-xylenol), cellulosederivatives (e.g.cellulose esters, cellulosecarbamates and cellulose ethers), siliconeresin (e.g. polydimethylsiloxane, polymethylphenylsiloxane), and rubbersor elastomers (e.g. diene-based rubbers such as polybutadiene andpolyisoprene, styrene-butadiene copolymers, acrylonitrile-butadienecopolymers, acrylic rubbers, urethane rubbers and silicone rubbers).

Examples of the heat-curable resin include phenolic resins, urea resins,diallyl phthalate resins, melamine resins, guanamine resins, unsaturatedpolyester resins, polyurethane resins, epoxy resins, aminoalkyd resins,melamine-urea cocondensation resins, silicon resins and polysiloxaneresins. When using the heat-curable resin, if necessary, a crosslinkingagent, a curing agent such as a polymerization initiator, apolymerization accelerator, a solvent, a viscosity modifier, etc. may beadded and used.

Furthermore, from the viewpoint of increasing the hardness of the hardcoat layer, it is preferable to use a polyalkylene oxidechain-containing polymer (A) represented by the following chemicalformula (3) in combination with the compound (B) having a molecularweight of less than 10,000 and two or more reactive functional groups.

wherein X is a straight, branched or cyclic hydrocarbon chain solely ora combination thereof; the hydrocarbon chain may have a substituent; aheteroatom may be contained between the hydrocarbon chains; thehydrocarbon chain is a trivalent or more organic group having 3 to 10carbon atoms excluding the substituent; k denotes an integer from 3 to10; each of L₁ to L_(k) is independently a direct bond or a divalentgroup having one or more kinds of bonds selected from the groupconsisting of an ether bond, ester bond and urethane bond; each of R₁ toR_(k) is independently a straight-chain or branched hydrocarbon grouphaving 1 to 4 carbon atoms; each of n1, n2 to nk is an independentnumber; and each of Y₁ to Y_(k) independently denotes a compound residuehaving one or more reactive functional groups (b).

The polymer (A), the compound (B) and the reactive inorganic fineparticles (A) are reactive with each other. It is presumed that becausethe polymer (A) is cross-linked to the compound (B) and the reactiveinorganic fine particles (A), the hard coat film can be imparted withabrasion resistance.

[Polyalkylene Oxide Chain-Containing Polymer (A) Represented by ChemicalFormula (3)]

The polyalkylene oxide chain-containing polymer (A) is a polyalkyleneoxide chain-containing polymer having a molecular weight of 1,000 ormore and three or more reactive functional groups (b) at the endpositions thereof, and is represented by the following chemical formula(3).

wherein X is a straight, branched or cyclic hydrocarbon chain solely ora combination thereof; the hydrocarbon chain may have a substituent; aheteroatom may be contained between the hydrocarbon chains; thehydrocarbon chain is a trivalent or more organic group having 3 to 10carbon atoms excluding the substituent; k denotes an integer from 3 to10; each of L₁ to L_(k) is independently a direct bond or a divalentgroup having one or more kinds of bonds selected from the groupconsisting of an ether bond, ester bond and urethane bond; each of R₁ toR_(k) is independently a straight-chain or branched hydrocarbon grouphaving 1 to 4 carbon atoms; each of n1, n2 to nk is an independentnumber; and each of Y₁ to Y_(k) independently denotes a compound residuehaving one or more reactive functional groups (b).

In the chemical formula (3), X is a straight, branched or cyclichydrocarbon chain solely or a combination thereof; the hydrocarbon chainmay have a substituent; a heteroatom may be contained between thehydrocarbon chains; and the hydrocarbon chain is a trivalent or moreorganic group having 3 to 10 carbon atoms excluding the substituent. Inthe polyalkylene oxide chain-containing polymer (A) represented by thechemical formula (3), X corresponds to a short main chain having kbranching point (s) (k denotes the number of the branching point (s)).From the branching point (s), a polyalkylene oxide chain portion(O—R_(k))_(nk) is branched, which is a linear side chain.

The hydrocarbon chain contains a saturated hydrocarbon like —CH₂— or anunsaturated hydrocarbon like —CH═CH—. The cyclic hydrocarbon chain maycomprise an alicyclic compound or aromatic compound. A heteroatom suchas O or S may be contained between the hydrocarbon chains, and an etherbond, thioether bond, ester bond, urethane bond or the like may be alsocontained between the hydrocarbon chains. A hydrocarbon chain that isbranched from the straight or cyclic hydrocarbon chain via a heteroatomis included in the number of carbons of a substituent that will bedescribed below.

Specific examples of the substituent that may be contained in thehydrocarbon chain include a halogen atom, hydroxyl group, carboxylgroup, amino group, epoxy group, isocyanate group, mercapto group, cyanogroup, silyl group, silanol group, nitro group, acetyl group, acetoxygroup and sulfonic group. The substituent is not limited to the aboveexamples. As mentioned above, the substituent that may be contained inthe hydrocarbon chain also contains said hydrocarbon chain that isbranched from the straight or cyclic hydrocarbon via a heteroatom, suchas an alkoxy group (RO—, wherein R is a straight, branched or cyclicsaturated or unsaturated hydrocarbon chain), alkylthioether group (RS—,wherein R is a straight, branched or cyclic saturated or unsaturatedhydrocarbon chain) and alkyl ester group (RCOO—, wherein R is astraight, branched or cyclic saturated or unsaturated hydrocarbonchain).

X is a trivalent or more organic group having 3 to 10 carbon atomsexcluding the substituent. In X, if the number of the carbon atomsexcluding the substituent is less than 3, it becomes difficult to havethree or more polyalkylene oxide chain portions (O—RO_(k))_(nk), whichare linear side chains. On the other hand, if the number of the carbonatoms excluding the substituent of X exceeds 10, there are more softparts in a cured film and the hardness of the film is thus decreased,which is not preferable. The number of the carbon atoms excluding thesubstituent is preferably 3 to 7, more preferably 3 to 5.

X is not particularly limited if the above conditions are met. As X, forexample, there may be mentioned one having any of the followingstructures.

As the particularly preferred structure, there may be mentioned theabove structures (x-1), (x-2), (x-3), (x-7), etc.

Materials that are suitably used as the material of X include, forexample, polyalcohols which have three or more hydroxyl groups in amolecule thereof and 3 to 10 carbon atoms, such as 1,2,3-propanetriol(glycerol), trimethylolpropane, pentaerythritol and dipentaerythritol;polycarboxylic acids which have three or more carboxyl groups in amolecule thereof and 3 to 10 carbon atoms; and C3-C10 multiamine acidshaving three or more amino groups in a molecule thereof.

In the chemical formula (3), k denotes the number of the polyalkyleneoxide chain (O—R_(k))_(nk) in a molecule, which is an integer from 3 to10. If k is less than 3, that is, if the number of the polyalkyleneoxide chain is 2, no sufficient hardness can be obtained. If k exceeds10, there are more soft parts in a cured film and the hardness of thefilm is thus decreased, which is not preferable. Preferably, k is 3 to7. More preferably, k is 3 to 5.

In the chemical formula (3), each of L₁ to L_(k) is independently adirect bond or a divalent group having one or more kinds of bondsselected from the group consisting of an ether bond, ester bond andurethane bond. The divalent group having one or more kinds of bondsselected from the group consisting of an ether bond, ester bond andurethane bond may be an ether bond (—O—), ester bond (—COO—) or urethanebond (—NHCOO—) itself. Because of these bonds, the molecular chain ofthese bonds can be easily lengthened and is thus highly flexible, sothat it is easy to obtain high compatibility with other resincomponents.

Examples of the divalent group having one or more kinds of bondsselected from the group consisting of an ether bond, ester bond andurethane bond include —O—R—O—, —O(C═O)—R—O—, —O(C═O)—R—(C═O)O—,—(C═O)O—R—O—, —(C═O)O—R—(C═O)O—, —(C═O)O—R—O(C═O)—, —NHCOO—R—O—,—NHCOO—R—O(C═O)NH—, —O(C═O)NH—R—O—, —O(C═O)NH—R—O(C═O)NH—,—NHCOO—R—O(C═O)NH—, —NHCOO—R—(C═O) O—, —O(C═O) NH—R—(C═O) O—,—NHCOO—R—O(C═O)— and —O(C═O)NH—R—O(C═O)—. The R used here denotes astraight, branched or cyclic, saturated or unsaturated hydrocarbonchain.

Specific examples of the divalent group include residues formed byremoving active hydrogens from a diol (such as (poly) ethylene glycoland (poly) propylene glycol), dicarboxylic acid (such as fumaric acid,maleic acid and succinic acid), and diisocyanate (such as tolylenediisocyanate, hexamethylene diisocyanate and isophorone diisocyanate).The divalent group is not limited to the above examples.

In the chemical formula (3), (O—R_(k))_(nk) is a polyalkylene oxidechain which is a linear side chain having alkylene oxide as therepeating unit. Herein, each of R₁ to R_(k) is independently astraight-chain or branched hydrocarbon group having 1 to 4 carbon atoms.Examples of the alkylene oxide include methylene oxide, ethylene oxide,propylene oxide and isobutylene oxide. Suitably used as the alkyleneoxide are ethylene oxide and propylene oxide, which are a straight-chainor branched hydrocarbon group having 2 to 3 carbon atoms.

In the chemical formula (3), each of n1, n2 to nk is the number of therepeating unit of alkylene oxide R_(k)—O, and is an independent number.No particular limitation is imposed on n1, n2 to nk as long as theweight average molecular weight of all the molecules is 1,000 or more.Each of n1, n2 to nk may be different; however, their chain lengths arepreferably almost equal from the viewpoint of preventing the hard coatlayer from cracking with retaining the original hardness of the hardcoat layer when it is formed. Therefore, the difference in the repeatingunits between n1 to nk is preferably about 0 to 100, more preferablyabout 0 to 50, even more preferably about 0 to 10.

From the viewpoint of preventing the hard coat layer from cracking withretaining the original hardness of the hard coat layer when it isformed, each of n1, n2 to nk is preferably a number of 2 to 500, morepreferably a number of 2 to 300.

Each of Y₁ to Y_(k) independently denotes a reactive functional group bor a compound residue having one or more reactive functional groups (b).Because of this, three or more reactive functional groups (b) areprovided to the end positions of the polyalkylene oxide chain-containingpolymer.

In the case where each of Y₁ to Y_(k) is a reactive functional group bitself, as each of Y₁ to Y_(k), for example, there may be mentioned apolymerizable unsaturated group such as a (meth)acryloyl group.

In the case where each of Y₁ to Y_(k) is a compound residue having oneor more reactive functional groups (b), examples of the reactivefunctional groups include polymerizable unsaturated groups such as a(meth)acryloyl group, (meth)acryloyloxy group, vinyl group (CH₂═CH—),and CH₂═CR— (wherein R is a hydrocarbon group). No particular limitationis imposed on the compound residue as long as the reactive functionalgroups (b) are appropriately selected so as to be reactive with thereactive inorganic fine particles (A) and/or the compound (B) that willbe described below. In the case where each of Y₁ to Y_(k) is a compoundresidue, the number of the reactive functional group(s) b of Y₁ to Y_(k)may be one. However, from the viewpoint of hardness of the resultinghard coat layer, the number is more preferably two or more, so that thecross-linking density of the hard coat layer is increased further.

In the case where each of Y₁ to Y_(k) is a compound residue having oneor more reactive functional groups (b), the compound residue is aresidue formed by removing the reactive substituent or a part of thereactive substituent (such as hydrogen) from a compound which has atleast one or more reactive functional groups (b) and a differentreactive substituent.

Specific examples of a compound residue having an ethylenicallyunsaturated group include residues formed by removing, from each of thefollowing compounds, a reactive substituent other than the ethylenicallyunsaturated group or a part of the reactive substituent (such ashydrogen) such as (meth)acrylic acid, hydroxyethyl(meth)acrylate,hydroxypropyl (meth)acrylate and pentaerythritol tri(meth)acrylate, butmay not be limited thereto.

The molecular weight of the polyalkylene oxide chain-containing polymer(A) used in the present invention is 1,000 or more, preferably 5,000 ormore, more preferably 10,000 or more, from the viewpoint of impartingflexibility to a cured layer and preventing the same from cracking.

Examples of commercial products containing the polyalkylene oxidechain-containing polymer (A) represented by the chemical formula (3)include BEAMSET 371 (product name; manufactured by Arakawa ChemicalIndustries, Ltd.), DIABEAM UK-4153 (product name; manufactured by:Mitsubishi Rayon Co., Ltd.; in the chemical formula (3), X is (x-7); kis 3; each of L₁ to L₃ is a direct bond; each of R₁ to R₃ is ethylene;the total of n1, n2 and n3 is 20; and each of Y₁ to Y₃ is an acryloyloxygroup.).

The content of the polymer (A) is preferably 5 to 100 parts by weight,more preferably 10 to 50 parts by weight, with respect to 100 parts byweight of the compound (B) that will be described below. If the contentof the polymer (A) is 5 parts by weight or more with respect to 100parts by weight of the polymer (B), flexibility and stability can beimparted to a cured film. If the content is 100 parts by weight or less,a cured film can retain its hardness.

[Compound (B) Having a Molecular Weight of Less than 10,000 and Two orMore Reactive Functional Groups (b)]

The compound (B) having a molecular weight of less than 10,000 and twoor more reactive functional groups (b) increases the hardness of thehard coat layer in corporation with the reactive inorganic fineparticles (A), thereby imparting sufficient abrasion resistance andhardness to the hard coat layer. One having the structure of the polymer(A) is, however, excluded from the compound (B) having a molecularweight of less than 10,000 and two or more reactive functional groups(b).

In the present invention, the compound (B) may be selected from a widerange of compounds having sufficient abrasion resistance and reactivefunctional groups (b) which are, when combined with the polymer (A) andthe reactive inorganic fine particles (A), reactive with them. Thecompound (B) may be a single compound or a mixture of two or more kindsof compounds.

In the compound (B) having a molecular weight of less than 10,000 andtwo or more reactive functional groups (b), from the viewpoint ofincreasing the cross-linking density of a cured film and impartinghardness to the film, the number of the functional groups b which arecontained in one molecule is preferably three or more. When the compound(B) is an oligomer having a molecular weight distribution, the number ofthe reactive functional groups (b) is expressed by an average number.

The molecular weight of the compound (B) is preferably less than 5,000from the viewpoint of increasing the hardness of the hard coat layer.

Specific examples of the compound (B) are listed below. However, thecompound (B) used in the present invention is not limited to thefollowing examples.

Specific examples of the compounds having polymerizable unsaturatedgroups include polyfunctional (meth)acrylate monomers having two or morepolymerizable unsaturated groups in a molecule including difunctional(meth)acrylate compounds such as 1,6-hexanediol di(meth)acrylate,neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, andisocyanuric acid ethylene oxide-modified di(meth)acrylate; trifunctional(meth)acrylate compounds such as trimethylolpropane tri(meth)acrylateand EO-, PO-, and epichlorohydrin-modified products thereof,pentaerythritol tri(meth)acrylate, glycerol tri(meth)acrylate and EO-,PO-, and epichlorohydrin-modified products thereof, isocyanuric acidEO-modified tri(meth)acrylate (e.g. ARONIXM-315 (product name;manufactured by: TOAGOSEI Co., Ltd.), tris(meth)acryloyl oxyethylphosphate, phthalicacid-hydrogen-(2,2,2-tri-(meth)acryloyloxymethyl)ethyl, and glyceroltri(meth)acrylate and EO-, PO-, and epichlorohydrin-modified productsthereof; tetrafunctional (meth)acrylate compounds such aspentaerythritol tetra(meth)acrylate and EO-, PO-, andepichlorohydrin-modified products thereof, and ditrimethylolpropanetetra(meth)acrylate; pentafunctional (meth)acrylate compounds such asdipentaerythritol penta(meth)acrylate and EO-, PO-, epichlorohydrin-,fatty acid-, alkyl-, and urethane-modified products thereof;hexafunctional (meth)acrylate compounds such as dipentaerythritol hexa(meth)acrylate and EO-, PO-, epichlorohydrin-, fatty acid-, alkyl-, andurethane-modified products thereof, and sorbitol hexa (meth)acrylate andEO-, PO-, epichlorohydrin-, fatty acid-, alkyl-, and urethane-modifiedproducts thereof.

Also, the examples include (meth)acrylate oligomers (or prepolymers)include epoxy(meth)acrylate obtained by addition reaction of glycidylether with (meth)acrylic acid or a monomer having a carboxylic acidbase; urethane (meth)acrylate obtained by addition reaction of areactant of polyol and polyisocyanate with (meth)acrylate having ahydroxyl group; polyester acrylate obtained by esterification ofpolyester polyol obtained from polyol and polyprotic acid with(meth)acrylic acid; and polybutadiene (meth)acrylate which is a(meth)acrylic compound having polybutadiene or a hydrogenated butadieneskeleton. If the reactive functional groups (b) of an essentialcomponent of the present invention are polymerizable unsaturated groups,urethane (meth)acrylate is particularly suitably used since it canimpart hardness and flexibility to a cured film.

Examples of glycidyl ether used in the epoxy (meth)acrylate include1,6-hexanediglycidyl ether, polyethyleneglycol glycidyl ether, bisphenolA type epoxy resins, naphthalene type epoxy resins, cardo epoxy resins,glycerol triglycidyl ether and phenolic novolac type epoxy resins.

Examples of polyol used in the urethane (meth)acrylate include1,6-hexanediglycidyl ether, polyethylene glycol, polypropylene glycol,polytetramethylene glycol, polycaprolactone diol, polycarbonate diol,polybutadiene polyol and polyester diol. Examples of polyisocyanate usedin the urethane (meth)acrylate include tolylene diisocyanate, xylylenediisocyanate, diphenylmethane diisocyanate, tetramethylxylenediisocyanate, hexamethylene diisocyanate, isophorone diisocyanate anddicyclohexylmethane diisocyanate. Examples of (meth)acrylate having ahydroxyl group used in the urethane (meth)acrylate include2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate,4-hydroxybutyl(meth)acrylate, pentaerythritol (meth)acrylate andcaprolactone-modified 2-hydroxyethyl(meth)acrylate.

Examples of polyol used to produce the polyester polyol used in thepolyester acrylates include ethylene glycol, polyethylene glycol,propylene glycol, polypropylene glycol, neopentyl glycol,1,4-butanediol, trimethylolpropane and pentaerythritol. Examples of thepolyprotic acid include succinic acid, adipic acid, sebacic acid,phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid andpyromellitic acid.

As the compound (B) used in the present invention, a polymer representedby the following chemical formula (4) and having a molecular weight ofless than 10,000 may be also used.

wherein L denotes a linking group having 1 to 10 carbon atoms; q denotes0 or 1; R denotes a hydrogen atom or methyl group; A denotes thepolymeric unit of an optional vinyl monomer and may comprise a singlecomponent or a plurality of components; each of o and p denotes mol % ofeach polymeric unit; and p may be 0.

L in the chemical formula (4) denotes a linking group having 1 to 10carbon atoms, preferably a linking group having 1 to 6 carbon atoms,more preferably a linking group having 2 to 4 carbon atoms. L may have astraight-chain, branched or cyclic structure. L may have a hetero atomselected from O, N and S.

Preferred examples of the linking group L in the chemical formula (4)include *—(CH₂)₂—O—**, *—(CH₂)₂—NH—**, *—(CH₂)₄—O—**, *—(CH₂)₆—O—**,*—(CH₂)₂—O— (CH)₂—O—**, *—CONN— (CH₂)₃—O—**, *—CH₂CH(OH)CH₂—O—** and*—CH₂CH₂OCONH(CH₂)₃—O—**. The * used here represents a site linked tothe main chain of the polymer, and the ** represents a site linked to a(meth)acryloyl group.

In the chemical formula (4), R denotes a hydrogen atom or methyl group.From the viewpoint of curing reactivity, R is preferably a hydrogenatom.

In the chemical formula (4), o may be 100 mol %, that is, a singlepolymer. Also, o may be 100 mol % or a copolymer produced by mixing twoor more kinds of polymeric units which are represented by o mol %; andcontain a (meth)acryloyl group. The ratio of o top is not particularlylimited and may be appropriately selected from the viewpoints ofhardness, solubility in a solvent, optical transparency, etc.

In the chemical formula (4), A means the polymeric unit of an optionalvinyl monomer. A is not particularly limited and may be appropriatelyselected from the viewpoints of hardness, solubility in a solvent,optical transparency, etc. Furthermore, A may comprise a single vinylmonomer or a plurality of vinyl monomers depending on the intendedpurpose.

Examples of the vinyl monomer include vinyl ethers such as methyl vinylether, ethyl vinyl ether, t-butyl vinyl ether, cyclohexyl vinyl ether,isopropyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinylether, glycidyl vinyl ether and allyl vinyl ether; vinyl esters such asvinyl acetate, vinyl propionate and vinyl butyrate; (meth)acrylates suchas methyl (meth)acrylate, ethyl(meth)acrylate, hydroxyethyl(meth)acrylate, glycidyl methacrylate, allyl(meth)acrylate and(meth)acryloyloxypropyltrimethoxysilane; styrene derivatives such asstyrene and p-hydroxymethylstyrene; unsaturated carboxylic acids such ascrotonic acid, maleic acid and itaconic acid; and derivatives thereof.

As the compound (B), reactive oligomers may be used, which have a weightaverage molecular weight of less than 10,000 and an ethylenicallyunsaturated bond at the end positions thereof or as a side chainthereof. Examples of the reactive oligomers include resins having, asthe framework component, any of poly(methyl(meth)acrylate), polystyrene,poly(butyl (methacrylate), poly(acrylonitrile/styrene),poly(2-hydroxymethyl(meth)acrylate/methyl(meth)acrylate),poly(2-hydroxymethyl(meth)acrylate/butyl(meth)acrylate), and copolymersof these resins with a silicone resin.

As the above-mentioned compounds, commercial products may be used.Examples of urethane acrylates which have a weight average molecularweight of less than 10,000 and two or more polymerizable unsaturatedgroups include AH-600, AT-600, UA-306H, UA-306T and UA-306I (productnames; manufactured by: Kyoeisha Chemical Co., Ltd.); UV-1700B,UV-3000B, UV-3200B, UV-6300B, UV-6330B and UV-7000B (product names;manufactured by: Nippon Synthetic Chemical Industry Co., Ltd.); BEAMSET500 series (502H, 504H, 550B; product name; manufactured by: ArakawaChemical Industries, Ltd.); U-6HA, U-15HA and UA-32P, U-324A (productnames; manufactured by: Shin-Nakamura Chemical Co., Ltd.); and M-9050(product name; manufactured by: Toagosei Co., Ltd.). Among the above,examples of urethane (meth)acrylate that is suitably used in combinationwith the polymer (A) of the present invention include urethane(meth)acrylate which is obtained by the reaction between a monomer ormultimer of isophorone diisocyanate, pentaerythritol polyfunctionalacrylate and dipentaerythritol polyfunctional acrylate. Commercialproducts of the urethane (meth)acrylate include, for example, UV-1700B(product name; manufactured by: Nippon Synthetic Chemical Industry Co.,Ltd.).

Examples of epoxy acrylates that have a weight average molecularweightof less than 10,000 and two ormore polymerizable unsaturated groupsinclude SP-4060, SP-1450 and so on in the SP series and VR-60, VR-1950,VR-90, VR-1100 and so on in the VR series (product names; manufacturedby: Showa Highpolymer Co., Ltd.); UV-9100B, UV-9170B and so on (productnames; manufactured by: Nippon Synthetic Chemical Industry Co., Ltd.);and EA-6320/PGMAc, EA-6340/PGMAc and so on (product names; manufacturedby: Shin-Nakamura Chemical Co., Ltd.).

Examples of reactive oligomers that have a weight average molecularweight of less than 10,000 and two or more polymerizable unsaturatedgroups include AA-6, AS-6, AB-6, and AA-714SK in the Macromonomer series(product names; manufactured by: TOAGOSEI Co., Ltd.).

(Polymerization Initiator)

To initiate or promote the polymerization of the above-mentioned radicalpolymerizable functional group or cationic polymerizable functionalgroup, a radical polymerization initiator, a cationic polymerizationinitiator, a radical and cationic polymerization initiator or the likemay be appropriately selected for use, if necessary. Thesepolymerization initiators decompose by light irradiation and/or heatingto produce radicals or cations, thereby promoting radical polymerizationor cationic polymerization.

The radical polymerization initiator may be any radical polymerizationinitiator capable of releasing a substance which can initiate radicalpolymerization by light irradiation and/or heating. Examples ofphoto-radical polymerization initiators include imidazole derivatives,bisimidazole derivatives, N-aryl glycine derivatives, organic azidecompounds, titanocenes, aluminate complexes, organic peroxides,N-alkoxypyridinium salts and thioxanthone derivatives. Specific examplesinclude 1,3-di(tert-butyldioxycarbonyl)benzophenone,3,3′,4,4′-tetrakis(tert-butyldioxycarbonyl)benzophenone,3-phenyl-5-isoxazolone, 2-mercapto benzimidazole,bis(2,4,5-triphenyl)imidazole, 2,2-dimethoxy-1,2-diphenylethane-1-on(product name: Irgacure 651; manufactured by: Chiba Specialty Chemicals,Inc.), 1-hydroxy-cyclohexyl-phenyl-ketone (product name: Irgacure 184;manufactured by: Chiba Specialty Chemicals, Inc.),2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-on (productname: Irgacure 369; manufactured by: Chiba Specialty Chemicals, Inc.),bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)-phenyl)titanium) (product name: Irgacure 784; manufacturedby: Chiba Specialty Chemicals, Inc.), but may not be limited thereto.

The cationic polymerization initiator may be any cationic polymerizationinitiator capable of releasing a substance which can initiate cationicpolymerization by light irradiation and/or heating. Examples of thecationic polymerization initiator include sulfonic esters, imidesulfonates, dialkyl-4-hydroxysulfonium salts, arylsulfonicacid-p-nitrobenzyl esters, silanol-aluminum complexes and(η6-benzene)(η5-cyclopentadienyl)iron(II), and specific examples includebenzointosylate, 2,5-dinitro benzyl tosylate and N-tosilphthalic imide,but may not be limited thereto.

Examples of the polymerization initiator that can be used as bothradical polymerization initiator and cationic polymerization initiatorinclude aromatic iodonium salts, aromatic sulfonium salts, aromaticdiazonium salts, aromatic phosphonium salts, triazine compounds and ironarene complexes, and specific examples include iodonium salts such aschloride, bromide or borofluoride salts, hexafluorophosphate salts andhexafluoroantimonate salts of iodonium such as diphenyliodonium,ditolyliodonium, bis(p-tert-butylphenyl)iodonium andbis(p-chlorophenyl)iodonium; sulfoniumsalts such as chloride, bromide orborofluoride salts, hexafluorophosphate salts and hexafluoroantimonatesalts of sulfonium such as triphenylsulfonium,4-tert-butyltriphenylsulfonium and tris(4-methylphenyl)sulfonium; and2,4,6-substituted-1,3,5-triazine compounds such as2,4,6-tris(trichloromethyl)-1,3,5-triazine,2-phenyl-4,6-bis(trichloromethyl)-1,3,5-triazine and2-methyl-4,6-bis(trichloromethyl)-1,3,5-triazine, butmaynot be limitedthereto.

[Other Components]

In addition to the above essential components, an anti-static agent andanti-glare agent may be accordingly added to the hard coat layer.Furthermore, various kinds of additives such as a reactive ornon-reactive leveling agent and various kinds of sensitizers may bemixed. In the case of containing an anti-static agent and/or anti-glareagent, the anti-static properties and/or anti-glare properties may befurther imparted to the hard coat layer of the present invention.

Hereinafter, the production method of the hard coat film of the presentinvention will be explained.

As an embodiment of the hard coat film of the present invention, theremay be a hard coat film wherein a photocurable binder system is used asa curable binder system containing binder component (B), and the hardcoat layer is formed by coating the curable resin composition for thehard coat layer in which the reactive inorganic fine particles (A) areadded to the photocurable binder system is coated on the observer sidesurface of the transparent substrate film.

The hard coat layer can be formed by coating the curable resincomposition for the hard coat layer, obtained by mixing the reactiveinorganic fine particles (A) and constituents of the photocurable bindersystem in an appropriate solvent, on the transparent substrate film.

<Preparation of Curable Resin Composition for Hard Coat Layer>

The curable resin composition for the hard coat layer is prepared bymixing and dispersing the above components according to a generalpreparation method. For mixing and dispersing, a paint shaker or a beadmill may be used. When the reactive inorganic fine particles (A) areobtained in the state of being dispersed in a solvent, the curable resincomposition for the hard coat layer is prepared by adding the curablebinder system and other components including solvent accordingly theretoin the dispersed state, and mixing the resultant solution to disperse.

Examples of the solvent include alcohols such as isopropyl alcohol,methanol, ethanol, butanol and isobutylalcohol; ketones such as methylethyl ketone (MEK), methyl isobutyl ketone (MIBK) and cyclohexanone;esters such as methyl acetate, ethyl acetate and butyl acetate;halogenated hydrocarbons such as chloroform, methylene chloride andtetrachloroethane; aromatic hydrocarbon such as toluene and xylene; andmixtures thereof.

According to the preferred embodiment of the first aspect of theinvention, it is preferable a leveling agent other thanfluorine-containing compounds such as a silicone-based leveling agent isadded to the curable resin composition for the hard coat layer. Thecomposition for coating having the leveling agent added can impartcoating stability, slidability and anti-fouling properties to thesurface of a coating layer upon coating or drying, and the effect ofabrasion resistance can be imparted.

<Coating of Curable Resin Composition for Hard Coat Layer>

Examples of methods of coating the curable resin composition for thehard coat layer on the transparent substrate film include the rollcoating method, Meyer bar coating method, and the gravure coatingmethod. After coating the curable resin composition for the hard coatlayer, drying and UV curing are performed. By drying the curable resincomposition for the hard coat layer for several tens of seconds toseveral tens of minutes after coating, reactive inorganic fine particles(A) are unevenly distributed on the air interface side and aggregate.Examples of light source of ultraviolet ray include a super highpressure mercury lamp, a high pressure mercury lamp, a low pressuremercury lamp, a carbon-arc lamp, a black-light fluorescent light and ametal halide lamp. As the wavelength of the ultraviolet ray, thewavelength region of 190 to 380 nm can be used. Specific examples ofsources of electron beam include Cock-croft type, Van de Graaff type,resonance transformer type, insulating core transformer type, lineartype, Dynamitron type or high-frequency type electron beam accelerators.

By curing the constituents of the photocurable binder system, thereactive functional groups (a) of the reactive inorganic fine particles(A) and the reactive functional group (b) of the binder component (B)contained in the constituents of the photocurable binder system arecrosslinked to form a mesh structure. Thus, a hard coat layer is formed.

In the case of forming the hard coat layer by the curable resincomposition for the hard coat layer, it is preferable to cure thecurable resin composition for the hard coat layer by the gel fraction offrom 30% to 80%, in which more preferable lower limit is 35% or more,even more preferably 40% or more, and more preferable upper limit is 70%or less, even more preferably 60% or less, from the viewpoint ofexcellent adhesion between the hard coat layer and the transparentsubstrate film, and excellent abrasion resistance.

The gel fraction can be obtained, for example, by the following methodwhen the composition is an ultraviolet curing resin. Firstly, an inkcontaining components other than reactive inorganic fine particles (A)such as a monomer, an oligomer, a polymer and other additives among thecomponents of the curable resin composition for the hard coat layer isproduced as a sample, and coated on a PET substrate having a thicknessof 50 μm by a layer thickness having a thickness of 5 μm. The resultantfilm is radiated with various UV irradiation conditions in the rangefrom 10 to 100 mJ at intervals of 10 mJ to produce samples. Next, thesamples are cut in 10 cm square, and weight X as average of three timesof measurement is measured. After the samples are dipped in a solventcapable of solving the monomer (e.g. acetone, methyl ethyl ketone,methyl acetate, toluene, and mixed solvent thereof; in the case ofacrylate-based composition, representative examples include acetone andmethyl ethyl ketone) for 12 hours or more, each sample is removed fromthe solvent, sufficiently dried in an oven (60° C.×2 minutes). Then, theweight B of dried sample is measured. A difference of the weight Xbefore dipping in the solvent and the weight Y of dried sample isreferred to as Z. Finally, the gel fraction (%) per dose is calculatedusing the following formula:

Gel fraction(%)=100−Z/X

In the hard coat film of the first aspect of the invention, the layerthickness of the hard coat layer is preferably from 2 μm to 30 μm, morepreferably from 5 μm to 20 μm, from the viewpoint of excellent physicalproperties such as hardness and abrasion resistance, and excellentproductivity. By setting the layer thickness to 2 μm or more, sufficienthard coating performance can be imparted, and by setting the layerthickness to 30 μm or less, generation of crack can be prevented.

According to the first aspect of the invention, a hard coat filmprovided with a hard coat layer having high hard coating performance, sothat a scratch is not formed on the surface by the following steel woolscratch test can be provided.

(Steel Wool Scratch Test)

The surface of the hard coat layer is fractioned or rubbed with #0000steel wool by reciprocating the steel wool with a certain load (e.g. 500g/cm²) for 10 times at a speed of 50 mm/sec. The stroke width offriction is preferably from 5 to 15 cm.

If there is no scratch visually observed on the surface of the hard coatlayer in this test, the steel wool resistance is referred to as 500g/cm². If the load is changed to 1,000 g/cm² and there is no scratch inthe test, the steel wool resistance is referred to as 1,000 g/cm². Inthe present invention, the steel wool resistance is preferably 500 g/cm²or more, more preferably 1,000 g/cm² or more.

<Other Embodiments>

The hard coat film of the present invention is not limited to theembodiment shown in FIG. 1. For example, other layers may be provided onthe transparent substrate film 2, and the above described hard coatlayer 1 may be provided on such other layers. As such other layers,there may be a layer (hereinafter, it may be referred to as anintermediate layer) comprising a photocurable resin and a heat-curableresin between the transparent substrate film 2 and the hard coat layer1. By providing the intermediate layer, if the transparent substratefilm is thin (e.g. 30 to 50 μm), rigidity insufficient with thetransparent substrate film itself can be supplemented. Thereby, the hardcoat layer is less likely to largely modify, and the intermediate layercan follow modification of the transparent substrate film to lightenexternal stress applied to hard coat layer. A plurality of layers may beprovided between the transparent substrate film 2 and the hard coatlayer 1.

<Other Layers>

The hard coat film of the present invention basically comprises thetransparent substrate film and a hard coat layer. However, consideringthe functions and applications of the hard coat film, the hard coat filmof the present invention may contain one or more layers that will bedescribed below besides the hard coat later of the present invention.

Hereinafter, a low refractive index layer will be explained in detail.

[Low Refractive Index Layer]

A low refractive index layer is a layer which lowers reflectance ratioby light interference effect of a multilayer film when external light(e.g. fluorescent lamp, natural light, etc.) reflects on the surface ofan optical laminate. In the preferred embodiment of the presentinvention, the low refractive index layer is preferably formed on thehard coat layer. The low refractive index layer has lower refractiveindex than that of a layer disposed lower than the low refractive indexlayer.

In the preferred embodiment of the present invention, the refractiveindex of the hard coat layer adjacent to the low refractive index layeris 1.5 or more, and the refractive index of the low refractive indexlayer is 1.45 or less, preferably 1.42 or less.

The low refractive index layer is preferably constituted by one selectedfrom 1) a silica or magnesium fluoride-containing resin, 2) afluorine-based resin being a low refractive index resin, 3) a silica ormagnesium fluoride-containing fluorine-based resin, and 4) a silica ormagnesium fluoride thin film. For the resin other than the fluorineresin, a similar resin as one constituting the hard coat layer can beused.

As the fluorine-based resin, a polymerizable compound or its polymercontaining a fluorine atom at least in a molecule can be used. Thepolymerizable compound is not particularly limited, and for example, onehaving a curable reactive group such as a functional group curable withionizing radiation or a thermosetting polar group is preferable.

Also, there may be a compound having these reactive groupssimultaneously. Contrary to the polymerizable compound, the polymer hasno reactive group as above.

As the polymerizable compound having an ionizing radiation-curablegroup, a fluorine-containing monomer having an ethylenically unsaturatedbond can be widely used. The specific examples include fluoroolefinssuch as fluoroethylene, vinylidene fluoride, tetrafluoroethylene,hexafluoropropylene, perfluorobutadiene andperfluoro-2,2-dimethyl-1,3-dioxole. Examples of a polymerizable compoundhaving a (meth)acryloyl oxy group include (meth)acrylate compoundshaving a fluorine atom in a molecule such as2,2,2-trifluoroethyl(meth)acrylate,2,2,3,3,3-pentafluoropropyl(meth)acrylate,2-(perfluorobutyl)ethyl(meth)acrylate,2-(perfluorohexyl)ethyl(meth)acrylate,2-(perfluorooctyl)ethyl(meth)acrylate,2-(perfluorodecyl)ethyl(meth)acrylate, methyl α-trifluoromethacrylateand ethyl α-trifluoromethacrylate, and fluorine-containingpolyfunctional (meth)acrylic ester compounds having a fluoroalkyl group,a fluorocycloalkyl group or a fluoroalkylene group having 1 to 14carbons and at least three fluorine atoms, and at least two(meth)acryloyloxy groups in a molecule.

Examples of a preferred heat-curable polar group include groups forminga hydrogen bond such as a hydroxyl group, a carboxyl group, an aminogroup and an epoxy group, which are not only excellent in adhesion witha coating layer but also in affinity with inorganic super fine particlessuch as silica. Examples of a polymerizable compound having aheat-curable polar group include 4-fluoroethylene-perfluoroalkylvinylether copolymers; fluoroethylene-hydrocarbon-based vinyl ethercopolymers; and fluorine-modified products of an epoxy, polyurethane,cellulose, phenolic or polyimide resin.

Examples of a polymerizable compound having both ionizingradiation-curable group and heat-curable polar group include alkyl,alkenyl, aryl esters of partially or completely fluorinated acrylic ormethacrylic acid, vinyl ethers of completely or partially fluorinatedacrylic or methacrylic acid, vinyl esters of completely or partiallyfluorinated acrylic or methacrylic acid, and vinyl ketones of completelyor partially fluorinated acrylic or methacrylic acid.

Also, together with the polymerizable compound having a fluorine atom orthe polymer, each of resin components described in the curable resincomposition for the hard coat layer can be mixed and used. Further, acuring agent for curing a reactive group, various additives forimproving coatability and imparting anti-fouling properties, and asolvent can be accordingly used.

According to a preferred embodiment of the present invention, “fineparticles having voids” are preferably utilized as a low refractiveindex agent. “Fine particles having voids” can maintain the strength ofthe low refractive index layer, and decrease the refractive index. Inthe present invention, “fine particles having voids” means fineparticles which have a structure inside of the fine particles beingfilled with air and/or a porous structure body containing air, and inwhich the refractive index decreases inversely proportional to theoccupancy of air in the fine particles compared to the originalrefractive index of the fine particles. Also, a fine particle capable offorming a nano porous structure in at least a part of inside and/orsurface of the coating layer by a form, structure or aggregated state ofthe fine particles or a dispersed state of the fine particles inside ofthe coating layer is included in the present invention. The lowrefractive index layer using the fine particles can adjust therefractive index from 1.30 to 1.45.

As a preferred specific example of inorganic fine particles havingvoids, there may be silica fine particles prepared using a techniquedisclosed in JP-A No. 2001-233611. Also, silica fine particles obtainedby the methods disclosed in JP-ANo. 7-133105, JP-ANo. 2002-79616 andJP-ANo. 2006-106714. Since the silica fine particle having voids is easyto produce and the hardness is high, the strength of the low refractiveindex layer when the layer is formed by mixing the particles and abinder can be improved, and the refractive index can be adjusted in therange from about 1.20 to 1.45. Particularly, as a preferred specificexample of organic fine particles having voids, there may be hollowpolymer fine particles prepared using a technique disclosed in JP-A No.2002-80503.

As the fine particles capable of forming a nano porous structure atleast apart of inside and/or surface of the coating layer, in additionto the above silica fine particles, there may be a dispersion oraggregate of hollow fine particles, produced for the purpose ofenlarging the specific surface area, for incorporating in a slow-releasematerial adsorbing various chemical substances to column for filling anda porous portions on the surface, porous fine particles used for fixingcatalyst, an insulator or a low dielectric material. As specificexamples thereof, aggregates of porous silica fine particles amongcommercial products (product names: Nipsil and Nipgel) manufactured byNihon Silica Kogyo Co., Ltd., and colloidal silica UP series (productname; manufactured by Nissan Chemical Industries, Ltd.) having astructure in which silica fine particles are linked in a chain form, inthe preferred particle size of the present invention can be utilized.

The average particle diameter of “fine particles having voids” is from 5nm to 300 nm, preferably from 8 nm to 100 nm, more preferably from 10 nmto 80 nm. By having the average particle diameter of the fine particlesin the above range, excellent transparency can be imparted to the lowrefractive index layer.

(Formation of Low Refractive Index Layer)

In formation of the low refractive index layer, an appropriate solventis used if necessary, and the viscosity is preferably from 0.5 to 5 cps(25° C.), more preferably from 0.7 to 3 cps (25° C.), to obtain apreferred coatablity as a resin composition. By appropriately adjustingthe viscosity, an antireflection film excellent in visible light ray canbe attained, an uniform thin film without coating unevenness can beformed, and the low refractive index layer particularly excellent inadhesion to the substrate can be formed.

The curing means of the resin may be similar as one explained the hardcoat layer. In the case of utilizing heating means for curing treatment,for example, thermal polymerization initiator, which startspolymerization of the polymerizable compound generating radicals byheating is preferably added to the fluorine-based resin composition.

Further, the hard coat film of the present invention may be providedwith an anti-fouling layer, anti-glare layer and so on hereinafterdescribed.

[Anti-Fouling Layer]

According to the preferred embodiment of the present invention, for thepurpose of preventing fouling of the outermost surface of the lowrefractive index layer, an anti-fouling layer, preferably one havingprovided with an anti-fouling layer on the surface side opposite to onesurface of the substrate film having the low refractive index layerformed, may be provided. The anti-fouling layer can further improveanti-fouling properties and abrasion resistance of the hard coat film.

Specific examples of an anti-fouling agent include fluorine-basedcompounds and/or silicon-based compounds having low compatibility with aphotocurable resin composition having a fluorine atom in a molecule andbeing difficult to be added to the low refractive index layer, andfluorine-based compounds and/or silicon-based compounds havingcompatibility with a photocurable resin composition and fine particleshaving a fluorine atom in a molecule.

[Anti-Glare Layer]

An anti-glare layer may be formed between the transparent substrate filmand the hard coat layer or low refractive index layer. The anti-glarelayer may be formed by a resin and an anti-glare agent. As the resin,one explained in the hard coat layer can be similarly used.

In the preferred embodiment of the present invention, the anti-glarelayer preferably satisfies all of the following formulae, wherein theaverage particle diameter of the fine particles is R (μm), the maximumvalue of convex portion of convexoconcave of the anti-glare layer fromthe substrate surface in vertical direction is Hmax (μm), the averagedistance of the convexoconcave of anti-glare layer is Sm (μm), and theaverage inclination angle of the convexoconcave portion is θa:

8R≦Sm≦30R,

R<Hmax<3R,

1.3≦θa≦2.5, and

1≦R≦8

In another preferred example of the present invention, an anti-glarelayer which satisfies Δn=|n1-n2|<0.1, wherein the refractive index offine particles is n1 and the refractive index of resin composition isn2, and the haze value inside of the anti-glare layer is 55% or less ispreferable.

As an anti-glare agent, there may be fine particles, the form of whichmay be a spherical form, an elliptic form, etc., preferably sphericalform. There are inorganic and organic fine particles, in which oneformed by organic material is preferable. The fine particles preferablyhave anti-glare properties and transparency.

Specific examples of the fine particles include plastic beads, and onehaving transparency is preferable. Specific examples of the plasticbeads include a styrene bead (refractive index: 1.59), a melamine bead(refractive index: 1.57), an acrylic bead (refractive index: 1.49), anacrylic-styrene bead (refractive index: 1.54), a polycarbonate bead anda polyethylene bead. The added amount of the fine particles is fromabout 2 to 30 parts by weight, preferably from about 10 to 25 parts byweight, with respect to 100 parts by weight of the transparent resincomposition.

The layer thickness (cured) of the anti-glare layer is from 0.1 to 100μm, preferably from 0.8 to 20 μm. By setting the layer thickness in thisrange, the anti-glare layer can sufficiently exhibit its function.

<Additives>

The above described layers may further have other function, and may beformed by a composition containing components adding functions, forexample, an anti-static agent, a refractive index modifier, ananti-fouling agent and a hardness modifier.

[Anti-Static Agent (Conductive Agent)]

By including the anti-static agent in the above layers, dust attachmenton the surface of the optical laminate can be effectively prevented.Specific examples of the anti-static agent include various kinds ofcationic compounds having a cationic group, such as a quaternaryammonium salt, pyridinium salt and primary, secondary or tertiary aminogroup; anionic compounds having an anionic group such as a sulfonic acidbase, sulfuric ester base, phosphoric ester base and phosphonic acidbase; amphoteric compounds such as an amino acid-based amphotericcompound and aminosulfuric ester-based amphoteric compound; nonioniccompounds such as an amino alcohol-based nonionic compound,glycerin-based nonionic compound and polyethylene glycol-based nonioniccompound; organometallic compounds such as alkoxides of tin andtitanium; and metal chelate compounds such as acetylacetonate salts ofthe organometallic compounds. Furthermore, compounds produced byincreasing the molecular weight of the above compounds may also bementioned. In addition, as the anti-static agent, there may be usedmonomers or oligomers which contain a tertiary amino group, quaternaryammonium group or metallic chelate moiety and are polymerizable uponexposure to ionizing radiation, or polymerizable compounds includingorganometallic compounds which have a functional group and are like acoupling agent.

Also, electroconductive fine particles can be exemplified. Specificexamples of the electroconductive fine particles include fine particlesof metal oxides. Such metal oxides include, for example, ZnO (refractiveindex: 1.90; hereinafter, each of the numerical values in parenthesesrefers to the refractive index), CeO₂ (1.95), Sb₂O₂ (1.71), SnO₂(1.997), indium tin oxide (often abbreviated as ITO; 1.95), In₂O₃(2.00), Al₂O₃ (1.63), antimony-doped tin oxide (abbreviated as ATO; 2.0)and aluminum-doped zinc oxide (abbreviated as AZO; 2.0). The fineparticles have a particle diameter of 1 μm or less, i.e. submicron size.The average particle diameter of the electroconductive fine particles ispreferably from 0.1 nm to 0.1 μm. By setting the average particlediameter in this range, the electroconductive fine particles dispersedin a binder gives a composition which is able to form a highlytransparent layer which causes almost no haze and has excellent totallight transmittance. The average particle diameter of theelectroconductive metal oxide fine particles can be measured by thedynamic light scattering method.

As the anti-static agent, there may be also used electroconductivepolymers. Specifically, examples include aliphatic conjugatedpolyacetylene, aromatic conjugated poly(paraphenylene), heterocyclicconjugated polypyrrole or polythiophene, heteroatom-containingconjugated polyaniline, mixed conjugated poly(phenylenevinylene). Also,examples include a multi-chain type conjugated system which is aconjugated system having a plurality of conjugated chain in a moleculethereof, and an electroconductive complex which is a polymer formed bygraft- or block-copolymerization of said conjugated polymer chain with asaturated polymer.

The added amount of the anti-static agent is preferably from 5 to 250mass %, more preferably the upper limit is 100 or less and the lowerlimit is 7 or more, with respect to the amount of the binder resin(excluding the solvent). It is preferable to adjust the added amount tothe above range since transparency as an optical laminate can bemaintained, and anti-static performance can be imparted withoutadversely affecting properties such as hard coating performance.

Specific examples of formation of anti-static layer include a method offorming a deposited film by depositing or sputtering electroconductivemetal or electroconductive metal oxide on the upper surface of the hardcoat layer, and a method of forming a coating layer by coating the resincompos it ion having electroconductive fine particles dispersed in aresin.

In the case of forming the anti-static layer by deposition, examples ofthe anti-static agent include electroconductive metals andelectroconductive metal oxides such as antimony-doped indium tin oxide(hereinafter, it may be referred to as “ATO”) and indium tin oxide(hereinafter, it may be referred to as “ITO”). The thickness of thedeposited film being the anti-static layer is from 10 nm to 200 nm, morepreferably the upper limit is 100 nm or less and the lower limit is 50nm or more.

The anti-static layer may be formed by a coating liquid containing theanti-static agent. In this case, as the anti-static agent, one explainedin the anti-static agent being a function-imparting component can besimilarly used. In the case of forming a coating layer usingelectroconductive fine particles, a curable resin is preferably used. Asthe curable resin, one used for forming the hard coat layer can besimilarly used. To form the coating layer, a coating liquid containingthe electroconductive fine particles in the curable resin is coated by acoating method such as the roll coating method, the Meyer bar coatingmethod and the gravure coating method. After coating, drying and UVcuring are performed.

In the curing method of the ionizing radiation-curable resincomposition, curing is performed by irradiation of electron beam or UV.In the case of curing by electron beam, electron beam having energy of100 KeV to 300 KeV is used. In the case of UV curing, UV generated byray from a super high pressure mercury lamp, a high pressure mercurylamp, a low pressure mercury lamp, a carbon-arc lamp, a xenon arc lampor a metal halide lamp is used.

[Refractive Index Modifier]

By adding a refractive index modifier to the hard coat layer,anti-reflection properties on the surface of the hard coat layer can beadjusted. The refractive index modifier includes a low-refractive indexagent, a middle-refractive index agent and a high-refractive indexagent.

(1) Low-Refractive Index Agent

The low-refractive index agent has lower refractive index than that ofthe hard coat layer. In the preferred embodiment of the presentinvention, one constituted by a hard coat layer having a refractiveindex of 1.5 or more and a low-refractive index agent having arefractive index of less than 1.5, preferably 1.45 or less.

Specifically, the low-refractive index agent explained in the lowrefractive index layer can be preferably used. The layer thickness ofthe low-refractive index agent is preferably 1 μm or more since thislayer is the outermost layer and requires abrasion resistance andhardness.

(2) High-Refractive Index Agent/Middle-Refractive Index Agent

The refractive index of the high-refractive index agent and themiddle-refractive index agent may be set from 1.46 to 2.00. Themiddle-refractive index agent means one having a refractive index of1.46 to 1.80, and the high-refractive index agent means one having arefractive index of 1.65 to 2.00.

As the high-refractive index agent and the middle-refractive indexagent, fine particles can be exemplified. The specific examples(refractive index is shown in brackets) include zinc oxide (1.90),titania (2.3 to 2.7), ceria (1.95), tin-doped indium oxide (1.95),antimony-doped tin oxide (1.80), yttria (1.87) and zirconia (2.0).

[Leveling agent]

The hard coat layer may have a leveling agent added. Examples ofpreferred leveling agents include fluorine-contained andsilicone-contained leveling agents. The curable resin composition forthe hard coat layer having the leveling agent added can improvecoatability toward the surface of a coating layer upon coating ordrying, can impart slidability and anti-fouling properties as well asthe effect of abrasion resistance.

[Anti-Fouling Agent]

The hard coat layer may contain an anti-fouling agent. The main purposeof the anti-fouling agent is anti-fouling of the outermost surface ofthe optical laminate. The anti-fouling agent can further impart abrasionresistance to the optical laminate. Specifically, as the anti-foulingagent, additives that can exhibit water-repellency, oil-repellency andfingerprint wipe-off properties are effected. More specifically,fluorine-based compounds, silicon-based compounds and mixed compoundsthereof can be exemplified. Specific examples include silane couplingagents having a fluoroalkyl group such as2-perfluorooctylethyltriaminosilane, and particularly, one having anamino group can be preferably used.

[Hardness Modifier (High Curing Agent)]

A hardness modifier (high curing agent) may be added to the hard coatlayer for the purpose of improving the effect of abrasion resistance.Specific examples of the hardness modifier include ionizingradiation-curable resins containing polyfunctional (meth)acrylateprepolymer such as polyester (meth)acrylate, urethane (meth)acrylate andepoxy (meth)acrylate, or polyfunctional (meth)acrylate monomer oftrifunctional or more such as trimethylolpropane tri(meth)acrylate,pentaerythritol tetra(meth)acrylate, dipentaerythritolhexa(meth)acrylate alone or in combination of two or more kinds selectedtherefrom.

2. Invention of Second Aspect

The hard coat film according to the second aspect of the invention is ahard coat film in which a hard coat layer is provided on a transparentsubstrate film,

wherein the hard coat layer comprises a cured product of a curable resincomposition for the hard coat layer containing:

a reactive inorganic fine particle (A) having an average particlediameter of 30 nm to 100 nm, and having a reactive functional group (a)introduced by an organic component, which covers at least a part of asurface of the reactive inorganic fine particle (A), on the surface, and

a curable binder system containing a binder component (B) having areactive functional group (b) cross-linkingly reactive with the reactivefunctional group (a) of the reactive inorganic fine particle (A), andthe curable binder system itself also having curing reactivity; and

wherein the reactive inorganic fine particle (A) has densitydistribution in a thickness direction of the hard coat layer, in whichdensity of the reactive inorganic fine particle (A) is lowest at aninterface on a side opposite to a transparent substrate film side of thehard coat layer while the density of the reactive inorganic fineparticle (A) is highest at an interface and its vicinity on thetransparent substrate film side of the hard coat layer.

FIG. 3 is a cross-sectional view showing an example of the hard coatfilm of the present invention. The hard coat film 10 in FIG. 3 comprisesthe transparent substrate film 2 and the hard coat layer 1 layered onone surface side of the transparent substrate film 2. The hard coatlayer 1 contains reactive inorganic fine particles (A) 4 to improveabrasion resistance. In FIGS. 3 to 5, the scale size of the thicknessdirection (vertical direction in the figures) is largely exaggerated(enlarged) than the scale size of the planar direction (horizontaldirection in the figures) for simplification of explanation.

FIG. 4 is a view showing the cross section P1-P1 of FIG. 3 from thedirection perpendicular to the cross section P1, and schematicallyshowing an example of the distribution of the reactive inorganic fineparticles (A) 4 of the cross section P1. In FIG. 4, the density of theinorganic fine particles (A) 4 is low at the interface 30 and itsvicinity on the side opposite to the transparent substrate film 2 sideof the cross section P1, and the density of the inorganic fine particles(A) 4 is high at the interface 40 and its vicinity on the transparentsubstrate film 2 side of the cross section P1.

FIG. 5 is a view showing the cross section P2-P2 of FIG. 3 from thedirection perpendicular to the cross section P2, and schematicallyshowing an example of the distribution of the reactive inorganic fineparticles (A) 4 of the cross section

P2. In FIG. 5, the reactive inorganic fine particles (A) 4 are uniformlydispersed. The reactive inorganic fine particles (A) 4 do not form anisland structure, in which particles aggregate and the particles dottedin the cross section P2.

When the thickness directional cross section of the hard coat layer isdefined as P1 and the vertical-directional density of the reactiveinorganic fine particle (A) in the cross section P1 is defied as thenumber (particles/μm²) of the reactive inorganic fine particle (A) perunit area of the cross section P1, the density of the reactive inorganicfine particle (A) at any part in a region from the interface on the sideopposite to the transparent substrate film side to 500 nm in depth ofthe cross section P1 is preferably 150 particles/μm² or less, morepreferably from 50 particles/μm² to 100 particles/μm². Also, the densityof the reactive inorganic fine particle (A) at any part in a region fromthe interface of the transparent substrate film side of the crosssection P1 to the height ten times higher than the average particlediameter is preferably from 200 particles/μm² to 400 particles/μm², morepreferably from 200 particles/μm² to 300 particles/μm². Herein, “anypart” means a unit area randomly selected from the subject region.

Also, the number of the reactive inorganic fine particle (A) partiallyprojected from the interface on the side opposite to the transparentsubstrate film side of the hard coat layer is preferably 150 or less perunit area of the interface, more preferably 130 or less.

When a planar-directional cross section of the hard coat layer isdefined as P2 and the planar-direction density of the reactive inorganicfine particle (A) in the cross section P2 is def ined as the number(particles/μm²) of the reactive inorganic fine particle (A) per unitarea of the cross section P2, difference of densities of the reactiveinorganic fine particle (A) of any two parts in the cross section P2 atany height of the hard coat layer is preferably 30 particles/μm² orless, more preferably 20 particles/μm² or less.

The density of the reactive inorganic fine particle (A) is obtained bythe following method.

Cross section photographies of a thickness-directional cross section P1of the hard coat layer and a planar-directional cross section P2 of thehard coat layer are taken by SEM (scanning electron microscope)photographing. Next, the number of the reactive inorganic fine particles(A) in the region of 500 nm×500 nm is visually counted in the regionfrom the interface on the side opposite to the transparent substratefilm side of the cross section P1 to the depth of 500 nm. The obtainedvalue is converted into the number of the reactive inorganic fineparticles (A) per 1 μm² to obtain the vertical-direction density(particles/μm²). Similarly, the number of the reactive inorganic fineparticles (A) present in the range of 600 nm×600 nm in the cross sectionP2 is visually counted. The obtained value is converted into the numberof the reactive inorganic fine particles (A) per 1 μm² to obtain theplanar-direction density (particles/μm²).

Generally, curable resin composition, which forms the surface of thehard coat layer in a thickness of about several nm, dissolves in analkali solution upon saponification treatment of the hard coat film. Ifthe reactive inorganic fine particles (A) partially protrude from theinterface on the side opposite to the transparent substrate film side ofthe hard coat layer, the curable resin composition around the protrudedinorganic fine particles (A) dissolves in an alkali solution. Thereby, aslight void is generated between the inorganic fine particles (A) andthe curable resin composition therearound, and the inorganic fineparticles (A) easily elute or drop from the surface of the hard coatlayer.

To the contrary, by setting the density of the reactive inorganic fineparticles (A) to the above region, the number of the reactive inorganicfine particles (A) at an interface and its vicinity on the side oppositeto the transparent substrate film side of the hard coat layer, that is,the number of the inorganic fine particles (A) which elute or drop fromthe surface of the hard coat layer can be decreased. Hence, the hardcoat film of the present invention exhibits excellent saponificationresistance. Also, by using the hard coat film, a protecting film is notnecessary upon saponification treatment so that the number of processesand the material cost can be reduced.

<Transparent Substrate Film>

Since the transparent substrate film used in the first aspect of theinvention can be similarly used as the transparent substrate film usedfor the second aspect of the invention, most of the explanation thereofare omitted.

<Hard Coat Layer>

The hard coat layer used for the second aspect of the invention ismostly common with on used for the first aspect of the invention. Thefeature of the second aspect of the invention is as below.

The hard coat layer used for the second aspect of the inventionpreferably has a hardness of 4H or more on the surface of the hard coatlayer by a pencil hardness test.

The layer thickness of the hard coat layer used for the second aspect ofthe invention is preferably from 1 μm to 100 μm, more preferably from 5μm to 30 μm, from the viewpoint of abrasion resistance.

[Reactive Inorganic Fine Particles (A)]

Since the transparent substrate film used in the first aspect of theinvention can be similarly used as the transparent substrate film usedfor the second aspect of the invention, most of the explanation thereofare omitted. The feature of the second aspect of the invention is asbelow.

As the reactive inorganic fine particle (A) used in the second aspect ofthe invention, a non-hollow particle not having a void or porousstructure inside of the particle is preferably used rather than aparticle having a void or porous structure inside of the particle suchas a hollow particle. Since the hollow particle has a void or porousstructure inside of the particle, the hollow particle has lower hardnessthan the non-hollow particle, and the hollow particle has smallerapparently specific gravity (mass per unit volume averaged includinghollow parts) than the non-hollow particle so that the hollow particlesat an interface and its vicinity on the side opposite to the transparentsubstrate film side of the hard coat layer easily increase. Hence, it ispreferable to use a non-hollow particle having high hardness and highspecific gravity compared to a hollow particle for the reactiveinorganic fine particle (A).

The average particle diameter of the reactive inorganic fine particles(A) of the second aspect of the invention is from 30 nm to 100 nm,preferably from 40 nm to 60 nm. By setting the average particle diameterto the reactive inorganic fine particles (A) to 30 nm or more, abrasionresistance can be imparted to the hard coat layer, the diffusioncoefficient of the reactive inorganic fine particles (A) can bedecreased, and the density of the reactive inorganic fine particles (A)in an interface and its vicinity on the side opposite to the transparentsubstrate film side of the hard coat layer can be decreased. Also, bysetting the average particle diameter of the reactive inorganic fineparticles (A) to 100 nm or less, the crosslinking point in matrix withrespect to the content can be increased, and a hard coat layer havinghigh film strength can be obtained.

The reactive inorganic fine particles (A) preferably have a narrowparticle size distribution and are monodispersed from the viewpoint ofmaintaining the recovery rate when the resin is used alone withoutdeteriorating transparency and significantly improving hardness.

The average particle diameter of fine particles means the 50%, particlediameter (d50 median diameter) of fine particles, which is obtained whenfine particles in a solution are measured by dynamic light scatteringand the particle size distribution thus obtained is expressed by acumulative distribution. The average particle diameter may be measuredby means of Microtrac particle size analyzer manufactured by NikkisoCo., Ltd.

The reactive inorganic fine particles (A) may be aggregated particles.If aggregated particles are used, it is preferable that not only theprimary particle size but also the secondary particle size is in theabove range.

When silane is used as the surface modification compound for preparingthe reactive inorganic fine particles (A) used in the second aspect ofthe invention, silane at least partially having an organic residuesubstituted by fluorine may be used.

(Formation of Hard Coat Layer in Second Aspect)

In the case of forming the hard coat film of the second aspect of theinvention, similarly as the first aspect, the curable resin compositionfor the hard coat layer is prepared, and coated on the transparentsubstrate film followed by drying.

The coating method is not particularly limited as long as it canuniformly apply the curable resin composition onto the surface of thetransparent substrate film. For example, there may be used various kindsof methods such as a spin coating method, a dipping method, a sprayingmethod, a slide coating method, a bar coating method, a roll coatingmethod, a meniscus coating method, a flexo printing method, ascreenprinting method and a bead coater method.

The coating amount on the transparent substrate film varies depending onrequired performance of a hard coat film to be obtained, but ispreferably from 1 g/m² to 30 g/m², more preferably from 5 g/m² to 25g/m², after drying.

As the drying method, for example, there may be drying under reducedpressure, drying by heating, or a combination thereof. For example, inthe case of using a ketone-based solvent as the solvent, the drying stepis performed at a temperature in the range normally from roomtemperature to 80° C., preferably from 40° C. to 60° C., and for a timeperiod from 20 seconds to 3 minutes, preferably from 30 seconds to 1minute.

The reactive inorganic fine particles (A) uniformly dispersed in thecurable resin composition for the hard coat layer are unevenlydistributed near the interface on the transparent substrate film side inthe drying process.

Next, the coating layer in the coating layer obtained by coating anddrying the curable resin composition for the hard coat layer is lightradiated and/or heated depending on the reactive functional groupcontained in the curable resin composition to be cured. Thereby, thereactive functional groups (a) of the reactive inorganic fine particles(A) and the reactive functional group (b) of the binder component (B)contained in the constituents of the curable resin composition arecrosslinked, so that a hard coat layer constituted with a cured productof the curable resin composition is formed. Thus, the hard coat film ofthe present invention can be obtained.

For light radiation, mainly, UV, visible light, electron beam, ionizingradiation, etc. is used. In the case of UV curing, UV from ray of asuper high pressure mercury lamp, high pressure mercury lamp, lowpressure mercury lamp, carbon-arc lamp, xenon arc lamp or metalhallidelamp is used. The dose of energy beam source is about 50 to 5,000 mJ/cm²as the integral exposure amount at the UV wavelength of 365 nm.

In the case of heating after the light irradiation, the coating layer isheated normally at a temperature from 40° C. to 120° C. The coatinglayer may be left at room temperature (25° C.) for 24 hours or more topromote reaction. Heating treatment is generally performed from 40° C.to 120° C. Also, the reaction may be performed by leaving at roomtemperature (25° C.) for 24 hours or more.

EXAMPLES

Hereinafter, the present invention will be explained in detail withreference to examples. The scope of the present invention may not belimited to the following examples.

Hereinafter, methods of evaluation in Examples, procedure and evaluationresults of Example A series, and procedure and evaluation results ofExample B series will be sequentially explained. Example A series areexamples related to the first aspect of the invention. Example B seriesare examples related to the second aspect of the invention.

In Examples, “part(s)” represents “part(s) by weight” if notparticularly specified. Ones having an average particle diameter of ±10nm are used for all of the particle size distribution of monodispersedfine particles compounded in the curable resin composition.

EVALUATION METHODS

Evaluation methods used in Examples are as follows.

Evaluation 1 Pencil Hardness

The pencil hardness of the surface of the obtained hard coat layer wasevaluated in accordance with JIS K5600-5-4 (1999). Five lines were drawnby a pencil having a hardness of 4H applying a load of 500 g. Then,presence of scratches on the hard coat layer was visually observed andevaluated according to the following criteria.

<Evaluation Criteria>

Evaluation ⊚: there was 0 to 1 line of scratch (pencil hardness is 4H).Evaluation ∘: there were 2 to 3 lines of scratches (corresponding to thepencil hardness of about 3H).Evaluation x: there were 4 to 5 lines of scratches.

Evaluation 2 Steel Wool Resistance (SW Resistance)

The surface of the hard coat layer of the obtained hard coat film wasfrictioned or rubbed with #0000 steel wool by reciprocating the steelwool with a load of 1,000 g/cm² for 10 times. Then, presence of peelingof the hard coat layer was visually observed, and evaluated according tothe following criteria.

<Evaluation Criteria>

Evaluation ⊚: there was no scratch (steel wool resistance was 1,000g/cm²).Evaluation ∘: there were 1 to 9 lines of scratches.Evaluation x: there were 10 lines or more of scratches.

Evaluation 3 Saponification Resistance

The obtained hard coat film (double the size of A4) was dipped in 200 mlof a 2N sodium hydroxide aqueous solution at 60° C. for two minutes.Then, the hard coat film was rinsed by pure water for saponificationtreatment. Next, the sodium hydroxide aqueous solution after thesaponification treatment was collected, and condensed by heat at 100° C.Then, pure water was added followed by further addition of nitric acidto make the solution become acid. The Si content in the sodium hydroxideaqueous solution was measured by ICP emission spectrometric analysis andevaluated.

<Evaluation Criteria>

Evaluation ⊚: the Si content in the sodium hydroxide aqueous solutionwas less than 2.0 μg/g.Evaluation ∘: the Si content in the sodium hydroxide aqueous solutionwas from 2.0 to 8.0 μg/g.Evaluation x: the Si content in the sodium hydroxide aqueous solutionwas more than 8.0 μg/g.

Example A Series Invention of First Aspect Production Example A1-1Preparation of Reactive Inorganic Fine Particles (i) (1) SurfaceAdsorbed Ion Removal

Aqueous dispersion colloidal silica (product name: SNOWTEX 20;manufactured by Nissan Chemical Industries, Ltd.; pH9 to 10; particlesize: 20 nm) was subjected to ion exchange using 400 g of acation-exchange resin (product name: Diaion SK1B; manufactured by:Mitsubishi Chemical Corporation) for 3 hours. Next, ion exchange wasperformed using 200 g of an anion-exchange resin (product name: DiaionSA20A; manufactured by: Mitsubishi Chemical Corporation) for 3 hoursfollowed by rinsing. Thus, an aqueous dispersion of silica fineparticles having a concentration of solid content of 20 wt % wasobtained.

The Na₂O content of the aqueous dispersion of the silica fine particleswas 7 ppm per silica fine particle.

(2) Surface Treatment (Introduction of Monofunctional Monomer)

150 mL of isopropanol, 4.0 g of 3,6,9-trioxadecanoate and 4.0 g ofmethacrylic acid were added to 10 g of the aqueous dispersion of thesilica fine particles after the above treatment (1), and agitated for 30minutes to mix.

The obtained mixture was agitated while heating at 60° C. for 5 hours.Thus, a silica fine particles dispersion liquid having a methacryloylgroup introduced on the surface of the silica fine particle wasobtained. Distilled water and isopropanol were distilled away from theobtained silica fine particles dispersion liquid by means of a rotaryevaporator while methyl ethyl ketone was added to prevent drying, sothat the amount of remained water and isopropanol was 0.1 wt % at theend. Thus, a silica-dispersed methyl ethyl ketone solution having asolid content of 50 wt % was obtained.

Thus obtained reactive inorganic fine particles (i) was measured bymeans of Nanotrac particle size analyzer manufactured by Nikkiso Co.,Ltd. The result was an average particle diameter of d50=21 nm. Also, theamount of the organic component covering the surface of the silica fineparticles was measured by thermogravimetric analysis, and the result was4.05×10⁻³ g/m².

Production Example A1-2 Preparation of Reactive Inorganic Fine Particles(i-2)

Similarly as Production example 1-1, the surface adsorbed ion removaland the surface treatment were performed except that an aqueousdispersion colloidal silica (product name: SNOWTEX XS; manufactured byNissan Chemical Industries, Ltd.; pH9 to 10; particle size: 5 nm) wasused instead of aqueous dispersion silica having a particle size of 20nm used in Production example A1-1.

Thus obtained reactive inorganic fine particles (i-2) were measured bymeans of the above particle size analyzer. The result was an averageparticle diameter of d50=5 nm. Also, the amount of the organic componentcovering the surface of the silica fine particles was measured bythermogravimetric analysis, and the result was 7.05×10⁻³ g/m².

Production Examples A1 to A3 Preparation of Reactive Inorganic FineParticles (i-3)

Similarly as Production example 1-1, the surface adsorbed ion removaland the surface treatment were performed except that an aqueousdispersion colloidal silica (product name: SNOWTEX 50; manufactured byNissan Chemical Industries, Ltd.; pH9 to 10; particle size: 25 nm) wasused instead of aqueous dispersion silica having a particle size of 20nm used in Production example A1-1.

Thus obtained reactive inorganic fine particles (i-3) were measured bymeans of the above particle size analyzer. The result was an averageparticle diameter of d50=26 nm. Also, the amount of the organiccomponent covering the surface of the silica fine particles was measuredby thermogravimetric analysis, and the result was 3.24×10⁻³ g/m².

Production Examples A1 to A4 Preparation of Reactive Inorganic FineParticles (i-4))

Similarly as Production example 1-1, the surface adsorbed ion removaland the surface treatment were performed except that an aqueousdispersion colloidal silica (product name: SNOWTEX XL; manufactured byNissan Chemical Industries, Ltd.; pH9 to 10; particle size: 60 nm) wasused instead of aqueous dispersion silica having a particle size of 20nm used in Production example A1-1.

Thus obtained reactive inorganic fine particles (i-4) were measured bymeans of the above particle size analyzer. The result was an averageparticle diameter of d50=63 nm. Also, the amount of the organiccomponent covering the surface of the silica fine particles was measuredby thermogravimetric analysis, and the result was 2.04×10⁻³ g/m².

Production Example A2 Preparation of Reactive Inorganic Fine Particles(ii)

In dried air, 20.6 parts by weight of isophorone diisocyanate wasdropped into a solution containing 7.8 parts by weight ofmercaptopropyltrimethoxysilane and 0.2 parts by weight of dibutyl tindilaurate while agitating at 50° C. for 1 hour, followed by agitation at60° C. for 3 hours. Thereto, 71.4 parts by weight of pentaerythritoltriacrylate was dropped at 30° C. for 1 hour, followed by agitationwhile heating at 60° C. for 3 hours. Thus, a compound (1) was obtained.

Under nitrogen flow, a mixture containing 88.5 parts by weight (solidcontent: 26.6 parts by weight) of methanol silica sol (product name:OSCAL series; manufactured by: JGC Catalysts and Chemicals Ltd.;methanol dispersion liquid; particle size: 20 nm), 8.5 parts by weightof the above synthesized compound (1) and 0.01 parts by weight ofp-methoxyphenol was agitated at 60° C. for 4 hours. Next, after 3 partsby weight of methyltrimethoxysilane as a compound (2) was added to themixture and agitated at 60° C. for 1 hours, 9 parts by weight of methylo-formate ester was added followed by agitation while heating at thesame temperature for another one hour. Thus, reactive inorganic fineparticles (ii) were obtained.

Thus obtained reactive inorganic fine particles (ii) were measured bymeans of the above particle size analyzer. The result was an averageparticle diameter of d50=22 nm. Also, the amount of the organiccomponent covering the surface of the silica fine particles was measuredby thermogravimetric analysis, and the result was 7.08×10⁻³ g/m².

Example A1 (1) Preparation of Curable Resin Composition for Hard CoatLayer

The following components were mixed, and adjusted with a solvent so thatthe solid content is 50 wt %. Thus, a curable resin composition for ahard coat layer was prepared.

<Composition of Curable Resin Composition for Hard Coat Layer>

-   -   UV1700B (product name; manufactured by: Nippon Synthetic        Chemical Industry Co., Ltd.; 10 functional; molecular weight:        2,000): 70 parts by weight (solid content calibrated value)    -   Reactive inorganic fine particle (i) of Production example        (A1-1): 30 parts by weight (solid content calibrated value)    -   Methyl ethyl ketone: 100 parts by weight    -   Irgacure 184 (product name; manufactured by: Chiba Specialty        Chemicals, Inc.; radical polymerization initiator): 0.4 parts by        weight

(2) Production of Hard Coat Film

As the transparent substrate film, a triacetate cellulose (TAC) filmhaving a thickness of 80 μm was used. On the transparent substrate film,the curable resin composition for the hard coat layer prepared in (1)was coated by WET weight of 40 g/m² (weight when dried: 20 g/m²). Dryingwas performed at 50° C. for 30 seconds, and UV of 200 mJ/cm² wasirradiated. Thus, a hard coat film 10, a hard coat layer 1 of which hasa thickness of 10 μm, was produced. In Table 1, the above evaluationresults are shown.

Example A2

Similarly as Example A1, a curable resin composition for the hard coatlayer was prepared except that the reactive inorganic fine particles(ii) of Production example (A2) was used so that the solid content partby weight was 30 parts by weight instead of the reactive inorganic fineparticles (i) of Production example (A1-1) in the curable resincomposition for the hard coat layer of Example A1. Then, similarly asExample 1, a hard coat film was produced. In Table 1, the evaluationresults are shown.

The average particle number of the reactive inorganic fine particles (A)per unit area of a thickness-directional cross section of the hard coatlayer of the hard coat film was 1,100/μm². Also, the average particlenumber of the reactive inorganic fine particles (A) per unit area of athickness-directional cross section of the skin layer was 2,300/μm²(each of them is a calibrated value from STEM cross sectionphotography).

From the above results, the average particle number of the reactiveinorganic fine particles (A) per unit area of a thickness-directionalcross section of the skin layer was 2.1 times larger than the averageparticle number of the hard coat layer. The evaluation of both pencilhardness and SW resistance were “⊚” (see Table 1).

Example A3

Similarly as Example A1, a curable resin composition for the hard coatlayer was prepared except that 70 parts by weight of DPHA (product name:KAYARAD DPHA; manufactured by NIPPON KAYAKU CO., LTD.; six functional;molecular weight: 800) was used instead of UV1700B in the curable resincomposition for the hard coat layer of Example A1. Then, similarly asExample A1, a hard coat film was produced. In Table 1, the evaluationresults are shown.

Example A4

Similarly as Example A1, a curable resin composition for the hard coatlayer was prepared except that 30 parts by weight of reactive inorganicfine particles (i-2) (average particle diameter: 5 nm) of Productionexample (A1-2) was used instead of 30 parts by weight of reactiveinorganic fine particles (i) (average particle diameter: 21 nm) ofProduction example (A1-1) in the curable resin composition for the hardcoat layer of Example A1. Then, similarly as Example A1, a hard coatfilm was produced. In Table 1, the evaluation results are shown.

Example 5

Similarly as Example A1, a curable resin composition for the hard coatlayer was prepared except that 30 parts by weight of reactive inorganicfine particles (i-3) (average particle diameter: 26 nm) of Productionexample (A1-3) was used instead of 30 parts by weight of reactiveinorganic fine particles (i) (average particle diameter: 21 nm) ofProduction example (A1-1) in the curable resin composition for the hardcoat layer of Example A1. Then, similarly as Example A1, a hard coatfilm was produced. In Table 1, the evaluation results are shown.

Example A6

Similarly as Example A1, a curable resin composition for the hard coatlayer was prepared except that UV1700B was used by 90 parts by weight,and the reactive inorganic fine particles (i) of Production example(A1-1) was used by 10 parts by weight in the curable resin compositionfor the hard coat layer of Example A1. Then, similarly as Example A1, ahard coat film was produced. In Table 1, the evaluation results areshown.

Example A7

Similarly as Example A1, a curable resin composition for the hard coatlayer was prepared except that UV1700B was used by 40 parts by weight,and the reactive inorganic fine particles (i) of Production example(A1-1) was used by 60 parts by weight in the curable resin compositionfor the hard coat layer of Example A1. Then, similarly as Example A1, ahard coat film was produced. In Table 1, the evaluation results areshown.

Example A8

Similarly as Example A1, a hard coat film was produced except that acycloolefin polymer (COP) film having a thickness of 80 μm was usedinstead of the triacetate cellulose film as the transparent substratefilm in production of the hard coat film of Example A1. In Table 1, theevaluation results are shown.

Example A9

Similarly as Example A1, a hard coat film was produced except that apolyethylene terephthalate (PET) film having a thickness of 100 μm wasused instead of the triacetate cellulose film as the transparentsubstrate film in production of the hard coat film of Example A1. InTable 1, the evaluation results are shown.

Example A10

Similarly as Example A1, a hard coat film was produced except that anacrylic resin film having a thickness of 100 μm was used instead of thecellulosetriacetate film as the transparent substrate film in productionof the hard coat film of Example A1. In Table 1, the evaluation resultsare shown.

Comparative Example A1

Similarly as Example A1, a curable resin composition for the hard coatlayer was prepared except that 30 parts by weight (solid contentcalibration) of untreated silica fine particles (product name: SNOWTEXYL; manufactured by: Nissan Chemical Industries, Ltd.; average particlediameter: 10 nm, concentration of solid content: 30 wt %) was usedinstead of 30 parts by weight of the reactive inorganic fine particles(i) in the curable resin composition for the hard coat layer of ExampleA1. The untreated silica fine particles were used, but in the column ofreactive inorganic fine particles in Table 1, the solid content parts byweight and the average particle diameter are shown for descriptivepurposes. Also, since the silica fine particles are not treated, thereis no amount of the organic component. Similarly as Example A1, a hardcoat film was produced. In Table 1, the evaluation results are shown.

Comparative Example A2

Similarly as Example A1, a curable resin composition for the hard coatlayer was prepared except that 30 parts by weight (solid contentcalibration) of the reactive inorganic fine particles (i-4) having anaverage particle diameter of 63 nm was used instead of 30 parts byweight of the reactive inorganic fine particles (i) having an averageparticle diameter of 21 nm in the curable resin composition for the hardcoat layer of Example A1. Then, similarly as Example A1, a hard coatfilm was produced. In Table 1, the evaluation results are shown.

TABLE 1 Reactive inorganic fine particles (A) Average Amount of particlePart by organic Evaluation Transparent Curable diameter weight component1 2 substrate resin d₅₀ of solid ×10⁻³ Pencil SW film Type (nm) Typecontent (g/m²) hardness resistance Example A1 TAC UV-1700B 21 i 30 4.05⊚ ⊚ Example A2 TAC UV-1700B 22 ii 30 7.08 ⊚ ⊚ Example A3 TAC DPHA 21 i30 4.05 ⊚ ⊚ Example A4 TAC UV-1700B 5 i-2 30 7.05 ⊚ ⊚ Example A5 TACUV-1700B 26 i-3 30 3.24 ⊚ ⊚ Example A6 TAC UV-1700B 21 i 10 4.05 ◯ ⊚Example A7 TAC UV-1700B 21 i 60 4.05 ◯ ⊚ Example A8 COP UV-1700B 21 i 304.05 ⊚ ⊚ Example A9 PET UV-1700B 21 i 30 4.05 ⊚ ⊚ Example *1 UV-1700B 21i 30 4.05 ⊚ ⊚ A10 Comparative TAC UV-1700B 10 *2 30 N/A X X example A1Comparative TAC UV-1700B 63 i-4 30 2.04 ⊚ X example A2 *1: acrylic resin*2: untreated silica fine particles

As shown in Table 1, the hard coat film of Comparative example A1, whichdoes not contain the reactive inorganic fine particles, is inferior inabrasion resistance (both pencil hardness and SW resistance are “x”).Also, the hard coat film of Comparative example A2, which uses thereactive inorganic fine particles having an average particle diameter of63 nm, is inferior in the SW resistance. It can be assumed that this isbecause uneven distribution of the reactive inorganic fine particles inthe skin layer did not easily occur since the average particle diameterof the reactive inorganic fine particles was too large.

Since in the hard coat film obtained in each of Examples A1 to A10 ofthe present invention, the average particle diameter of the reactiveinorganic fine particles having the reactive functional group is from 5nm to 30 nm, and the reactive inorganic fine particles are unevenlydistributed on the air interface side of the hard coat layer to form theskin layer, the hard coating performance can be improved.

Example B Series Invention of Second Aspect Production Example B1Preparation of Reactive Inorganic Fine Particles (A) (1) (1) SurfaceAdsorbed Ion Removal

Aqueous dispersion colloidal silica (product name: SNOWTEX ZL;manufactured by Nissan Chemical Industries, Ltd.; pH9 to 10; particlesize: 90 nm) was subjected to ion exchange using 400 g of acation-exchange resin (product name: Diaion SK1B; manufactured by:Mitsubishi Chemical Corporation) for 3 hours. Next, ion exchange wasperformed using 200 g of an anion-exchange resin (product name: DiaionSA20A; manufactured by: Mitsubishi Chemical Corporation) for 3 hoursfollowed by rinsing. Thus, an aqueous dispersion of inorganic fineparticles having a concentration of solid content of 20 wt % wasobtained.

The Na₂O content of the aqueous dispersion of the inorganic fineparticles was 7 ppm per inorganic fine particle.

(2) Surface Treatment (Introduction of Monofunctional Monomer)

150 mL of isopropanol, 4.0 g of 3,6,9-trioxadecanoate and 4.0 g ofmethacrylic acid were added to 10 g of the aqueous dispersion of theinorganic fine particles after the above treatment (1), and agitated for30 minutes to mix.

The obtained mixture was agitated while heating at 60° C. for 5 hours.Thus, an inorganic fine particles dispersion liquid having amethacryloyl group introduced on the surface of the inorganic fineparticle was obtained. Distilled water and isopropanol were distilledaway from the obtained inorganic fine particles dispersion liquid bymeans of a rotary evaporator while methyl ethyl ketone was added toprevent drying, so that the amount of remained water and isopropanol was0.1 wt % at the end. Thus, a silica-dispersed methyl ethyl ketonesolution having a solid content of 50 wt % was obtained.

Thus obtained reactive inorganic fine particles (A) (1) was measured bymeans of Microtrac particle size analyzer manufactured by Nikkiso Co.,Ltd. The result was an average particle diameter of d50=93 nm. Also, theamount of the organic component covering the surface of the inorganicfine particles was measured by thermogravimetric analysis, and theresult was 4.05×10⁻³ g/m².

Production Example B2 Preparation of Reactive Inorganic Fine Particles(A) (2) (1) Surface Adsorbed Ion Removal

Similarly as Production example B1, an aqueous dispersion liquid ofinorganic fine particles having the surface adsorbed ion removed wereobtained.

(2) Surface Treatment (Introduction of Polyfunctional Monomer)

In similar manner as Production example B1, surface treatment wasperformed except that methacrylic acid was changed to dipentaerythritolpentaacrylate (product name: SR399; manufactured by Sartomer Company,Inc.) in Production example B1.

Thus obtained reactive inorganic fine particles (A) (2) were measured bymeans of the above particle size analyzer. The result was an averageparticle diameter of d50=93 nm. Also, the amount of the organiccomponent covering the surface of the inorganic fine particles wasmeasured by thermogravimetric analysis, and the result was 3.84×10⁻³g/m².

Production Example B3 Preparation of Reactive Inorganic Fine Particles(A) (3)

In dried air, 20.6 parts of isophorone diisocyanate was dropped into asolution containing 7.8 parts of mercaptopropyltrimethoxysilane and 0.2parts of dibutyl tin dilaurate while agitating at 50° C. for 1 hour,followed by agitation at 60° C. for 3 hours. Thereto, 71.4 parts ofpentaerythritol triacrylate was dropped at 30° C. for 1 hour, followedby agitation while heating at 60° C. for 3 hours. Thus, a compound (1)was obtained.

Under nitrogen flow, a mixture containing 88.5 parts by weight (solidcontent: 26.6 parts) of methanol silica sol (product name: OSCAL series;manufactured by: JGC Catalysts and Chemicals Ltd.; methanol dispersionliquid; number average particle diameter: 45 nm), 8.5 parts of the abovesynthesized compound (1) and 0.01 parts of p-methoxyphenol was agitatedat 60° C. for 4 hours. Next, after 3 parts of methyltrimethoxysilane asa compound (2) was added to the mixture and agitated at 60° C. for 1hours, 9 parts of methyl o-formate ester was added followed by agitationwhile heating at the same temperature for another one hour. Thus,crosslinkable inorganic fine particles were obtained. Thus obtainedreactive inorganic fine particles (A) (3) were measured by means of theabove particle size analyzer. The result was an average particlediameter of d50=49 nm. Also, the amount of the organic componentcovering the surface was measured by thermogravimetric analysis, and theresult was 7.08×10³ g/m².

Example B1 (1) Preparation of Curable Resin Composition for Hard CoatLayer

The following components were mixed, and adjusted with a solvent so thatthe solid content is 50 wt %. Thus, the curable resin composition forthe hard coat layer was prepared.

<Composition of Curable Resin Composition for Hard Coat Layer>

-   -   UV1700B (product name; manufactured by: Nippon Synthetic        Chemical Industry Co., Ltd.; urethane acrylate; 10 functional;        molecular weight: 2,000): 70 parts by weight (solid content        calibrated value)    -   Reactive inorganic fine particles (A) (1) (average particle        diameter: 93 nm) of Production example B1: 30 parts by weight        (solid content calibrated value)    -   Methyl ethyl ketone: 100 parts by weight    -   Irgacure 184 (product name; manufactured by: Chiba Specialty        Chemicals, Inc.; radical polymerization initiator): 0.4 parts by        weight

(2) Production of Hard Coat Film

As the transparent substrate film, a triacetate cellulose film having athickness of 80 μm was used. On the substrate, the curable resincomposition for the hard coat layer prepared in (1) was coated by WETweight of 40 g/m² (weight when dried: 20 g/m²). Drying was performed at50° C. for 30 seconds, and UV of 200 mJ/cm² was irradiated. Thus, a hardcoat film of Example B1 was produced.

Example B2

Similarly as Example B1, a hard coat film was obtained except that 30parts by weight of the reactive inorganic fine particles (A) (2)obtained in Production example B1 was used instead of the reactiveinorganic fine particles (A) (1) obtained in Production example B1 inproduction of the hard coat film of Example B1.

Example B3

Similarly as Example B1, a hard coat film was obtained except that 30parts by weight of the reactive inorganic fine particles (A) (3)obtained in Production example B3 was used instead of the reactiveinorganic fine particles (A) (1) obtained in Production example B1 inproduction of the hard coat film of Example B1.

Example B4

Similarly as Example B1, a hard coat film was obtained except that theaverage particle diameter of the reactive inorganic fine particles (A)(1) obtained in Production example B1 was set to d₅₀=63 nm and 70 partsby weight of dipentaerythritolhexaacrylate (DPHA) was used as the bindercomponent (B) in production of the hard coat film of Example B1.

Example B5

Similarly as Example B3, a hard coat film was obtained except that 90parts by weight of UV1700B was used as the binder component (B) and 10parts by weight of the reactive inorganic fine particles (A) (3)obtained in Production example B3 was used in production of the hardcoat film of Example B3.

Example B6

Similarly as Example B3, a hard coat film was obtained except that 40parts by weight of UV1700B was used as the binder component (B) and 60parts by weight of the reactive inorganic fine particles (A) (3)obtained in Production example B3 was used in production of the hardcoat film of Example B3.

Example B7

Similarly as Example B3, a hard coat film was obtained except that theaverage particle diameter of reactive inorganic fine particles (A) (3)obtained in Production example B3 was set to d₅₀=32 nm in production ofthe hard coat film of Example B3.

Example B8

Similarly as Example B3, a hard coat film was obtained except that theaverage particle diameter of reactive inorganic fine particles (A) (3)obtained in Production example B3 was set to d₅₀=100 nm in production ofthe hard coat film of Example B3.

Example B9

Similarly as Example B3, a hard coat film was obtained except that, asthe binder component (B), 50 parts by weight of UV1700B and 20 parts byweight of BEAMSET 371 (product name; manufactured by Arakawa ChemicalIndustries, Ltd.; polymer acrylate, molecular weight: 30,000) were usedin production of the hard coat film of Example B3.

Comparative Example B1

Similarly as Example B1, a hard coat film was obtained except that 30parts by weight of colloidal silica (product name: MEK-ST; manufacturedby Nissan Chemical Industries, Ltd.) having an average particle diameterof d₅₀=60 nm was used instead of the reactive inorganic fine particles(A) in production of the hard coat film of Example B1.

Comparative Example B2

Similarly as Example B3, a hard coat film was obtained except that theaverage particle diameter of the reactive inorganic fine particles (A)(3) obtained in Production example B3 was set to d₅₀=20 nm in productionof the hard coat film of Example B3.

TABLE 2 Reactive inorganic fine Binder component particles “A” “B”Average Content Content particle (part by Production (part by diameterPencil Type weight) method weight) (nm) Saponifiability hardness ExampleB1 UV1700B 70 1 30 93 ⊚ ⊚ Example B2 UV1700B 70 2 30 93 ⊚ ⊚ Example B3UV1700B 70 3 30 49 ⊚ ⊚ Example B4 DPHA 70 1 30 63 ⊚ ⊚ Example B5 UV1700B90 3 10 49 ⊚ ◯ Example B6 UV1700B 40 3 60 49 ⊚ ⊚ Example B7 UV1700B 70 330 32 ⊚ ⊚ Example B8 UV1700B 70 3 30 100 ⊚ ⊚ Example B9 UV1700B 50 3 3049 ⊚ ⊚ BEAMSET 20 371 Comparative UV1700B 70 — 30 60 X X example B1Comparative UV1700B 70 3 30 20 X ⊚ example B2

1. A hard coat film in which a hard coat layer is provided on atransparent substrate film, wherein the hard coat layer comprises acured product of a curable resin composition for the hard coat layercontaining: a reactive inorganic fine particle (A) having an averageparticle diameter of 30 nm to 100 nm, and having a reactive functionalgroup (a) introduced by an organic component, which covers at least apart of a surface of the reactive inorganic fine particle (A), on thesurface, and a curable binder system containing a binder component (B)having a reactive functional group (b) cross-linkingly reactive with thereactive functional group (a) of the reactive inorganic fine particle(A), and the curable binder system itself also having curing reactivity;and wherein the reactive inorganic fine particle (A) has densitydistribution in a thickness direction of the hard coat layer, in whichdensity of the reactive inorganic fine particle (A) is lowest at aninterface on a side opposite to a transparent substrate film side of thehard coat layer while the density of the reactive inorganic fineparticle (A) is highest at an interface and its vicinity on thetransparent substrate film side of the hard coat layer.
 2. The hard coatfilm according to claim 1, wherein when a thickness-directional crosssection of the hard coat layer is defined as P1 and avertical-directional density of the reactive inorganic fine particle (A)in the cross section P1 is de fined as a number (particles/μm²) of thereact ive inorganic fine particle (A) per unit area of the cross sectionP1, density of the reactive inorganic fine particle (A) at any part in aregion from the interface on the side opposite to the transparentsubstrate film side to 500 nm in depth of the cross section P1 is 150particles/μm² or less.
 3. The hard coat film according to claim 1,wherein a number of the reactive inorganic fine particle (A) partiallyprojected from the interface on the side opposite to the transparentsubstrate film side of the hard coat layer is 150 or less per unit areaof the interface.
 4. The hard coat film according to claim 1, whereinwhen a planar-directional cross section of the hard coat layer isdefined as P2 and a planar-directional density of the reactive inorganicfine particle (A) in the cross section P2 is defined as a number(particles/μm²) of the reactive inorganic fine particle (A) per unitarea of the cross section P2, difference of densities of the reactiveinorganic fine particle (A) of two parts in the cross section P2 at anyheight of the hard coat layer is 30 particles/μm² or less.
 5. The hardcoat film according to claim 1, wherein hardness of the hard coat layerwhen a pencil hardness test in accordance with JIS K5600-5-4 (1999) isperformed with a load of 500 g is 4H or more.
 6. The hard coat filmaccording to claim 1, wherein layer thickness of the hard coat layer isfrom 1 μm to 100 μm.
 7. The hard coat film according to claim 1, whereinthe organic component covering the reactive inorganic fine particle (A)is contained in the reactive inorganic fine particles (A) by 1.00×10⁻³g/m² or more per unit area of the inorganic fine particle before beingcovered.
 8. The hard coat film according to claim 1, wherein thereactive functional group (a) of the reactive inorganic fine particle(A) and the reactive functional group (b) of the binder component (B)have a polymerizable unsaturated group.
 9. The hard coat film accordingto claim 1, wherein the reactive inorganic fine particles (A) areobtained by dispersing inorganic fine particles in water and/or anorganic solvent serving as a dispersion media in the presence of one ormore kinds of surface modification compounds having a molecular weightof 500 or less selected from the group consisting of saturated orunsaturated carboxylic acid, acid anhydride, acid chloride, ester andacid amide corresponding to the carboxylic acid, amino acid, imine,nitrile, isonitrile, an epoxy compound, amine, a β-dicarbonyl compound,silane and a metallic compound having a functional group.
 10. The hardcoat film according to claim 9, wherein the surface modificationcompound is a compound having a hydrogen bond-forming group.
 11. Thehard coat film according to claim 9, wherein at least one kind of thesurface modification compound has a polymerizable unsaturated group tobe the reactive functional group (a).
 12. The hard coat film accordingto claim 1, wherein the reactive inorganic fine particles (A) areobtained by bounding a compound containing the reactive functional group(a) being introduced on the surface of the reactive inorganic fineparticle (A), a group represented by the following chemical formula (1),and a silanol group or a group producing the silanol group byhydrolysis, with metal oxide fine particles:-Q¹-C(=Q²)-NH—  Chemical formula (1) wherein Q¹ is NH, O (oxygen atom)or S (sulfur atom); and Q² is O or S.
 13. The hard coat film accordingto claim 1, wherein the binder component (B) is a compound having threeor more reactive functional groups (b).
 14. The hard coat film accordingto claim 1, wherein a content of the reactive inorganic fine particle(A) is from 10 to 60 wt % with respect to a total solid content.
 15. Thehard coat film according to claim 1, wherein the transparent substratefilm mainly comprises cellulose acylate, a cycloolefin polymer, anacrylate-based polymer or polyester.